Meet Our Team
We bring together the best minds and innovators in the industry. Meet our team of leaders, experts, and trusted advisors.

Avella Taylor
Regional Director

Michael Hall
Regional Director

Richard Vaughan
Regional Director

Ashton Gibbard
Associate Director

Kris Vulinovich
Associate Director

Joe Holmes
Associate Director

Alexander Dolejschka-Ang
Registered Valuer

Angus McDonald
Registered Valuer

Ben Williams
Valuer

Brian Stafford-Bush
Registered Valuer

Ewen Lilburn
Appointee Valuer

Gary Brunsdon
Registered Valuer

James Clark
Registered Valuer

Jason Wong
Registered Valuer
%20Qin.jpg)
Jeffrey Qin
Registered Valuer

Jessie Jiang
Registered Valuer

John Hickey
Registered Valuer

Kate Tubberty
Registered Valuer

Kurt Brunsdon
Registered Valuer

Leeane Gregory
Registered Valuer

Lionel Musson
Registered Valuer

Mark Davidson
Registered Valuer

Mark Grinlinton
Registered Valuer

Martyn Oostveen
Senior Rural Valuer

Mate Finlay
Valuer

Michael Baxter
Appointee Valuer

Michael Dempsey
Registered Valuer

Mike Mclean
Registered Valuer

Ming Zhao
Registered Valuer

Nick Westerkamp
Registered Valuer

Paul Sherrock
Registered Valuer

Ryan Thomson
Registered Valuer

Sasha Peters
Registered Valuer

Shelley Manson
Valuer

Simon-Peter Finlay
Registered Valuer

Steven Flexman
Registered Valuer

Tim McCabe
Registered Valuer

Tom Mabbott
Registered Valuer

Tony Mcewan
Registered Valuer

Tyson Gedge
Registered Valuer

Danielle Nikora
Graduate Valuer

William Tomlinson
Registered Valuer

Chris Knight
Group CEO

Johan Wikman
Chief Technology Officer

Lisa Billington
Group Chief Legal Officer

Scott Chapman
Managing Director

James Harkness
Chief Financial Officer

Avella Taylor
Formal Qualifications
- Registered Valuer in New Zealand (Member No. NZIV 3780)
- Member of the Property Institute New Zealand
- Property Institute of New Zealand Branch Committee Chair – Auckland
- Bachelor of Commerce (Property Valuation) - Curtin University of Technology Western Australia 2014
Industry Experience
Avella has several years’ experience as a valuer and has been employed by Opteon since 2013. She is the Regional Director of Government Services for New Zealand and leads the Government Department which undertakes valuations throughout New Zealand.
Areas of Expertise
- Valuations for mortgage purposes
- Residential valuations
- Asset valuations for financial reporting and insurance purposes
- Project management and delivery

Michael Hall
Formal Qualifications
- Registered Valuer - 2008 License No. 3495
- Member of the Property Institute of New Zealand (MPINZ)
- Bachelor of Property, Auckland University
Industry Experience
Michael is currently the Regional Director for the New Zealand Commercial & Industrial team but began his valuation career with Sheldon & Partners Limited in 2004 upon completing a Bachelor of Property at the University of Auckland. He went on to gain registration as a valuer in 2008.
Since that time Michael has specialised in a broad range of Commercial & Industrial valuations within Auckland with a strong focus on the North Shore and Rodney regions. Michael is “born & bred” on the North Shore, and this combined with having specialised in the region since 2004 has allowed him to develop strong relationships with local key stakeholders enabling him to provide accurate, timely and cost-effective advice.
Opteon New Zealand was established with the merger of Sheldons & Partners Limited, a practice based in Auckland New Zealand that had been in operation for some 40 years.
Areas of Expertise
- Commercial & Industrial valuations
- Pre-sale and pre-purchase advice
- Rental assessments
- Insurance valuations
- Tax depreciation valuations
- Subdivisional/development land valuations
- Asset valuations for financial reporting
- Development feasibility

Richard Vaughan
Formal Qualifications
- Registered Valuer
- Member of the Property Institute New Zealand
- Bachelor of Property – The University of Auckland
Industry Experience
Richard is a vastly experienced registered valuer whose breadth of experience ranges from established niche markets within Auckland and extending beyond taking in development projects across the Pacific and through the Middle East. Meticulous attention to detail, broad understanding of clients’ needs, and an engaging personality serve to ensure professional and competent advice is offered.
Richard joined Opteon through the merger of Sheldons & Partners Limited a long-established practice based in Auckland New Zealand that had been in operation for some 40 years.
Areas of Expertise
- Insurance Assessments
- Matrimonial Assessments
- Residential Specialist with expertise in Apartments, Lifestyle, Residential Block Land

Ashton Gibbard
Formal Qualifications
- Registered Property Valuer
- Bachelor of Business Studies (Valuation and Property Management)
Industry Experience
Ashton has been valuing since 2011 and has a wide knowledge base with experience across valuation sectors including rating valuations (roll maintenance and revaluations), financial reporting valuations, project managing national portfolio valuations, along with private market and insurance valuations. Ashton has worked on rating contracts throughout the lower and central North Island and across the Northland Region.
Areas of Expertise
- Multi-unit residential investment property valuation
- Valuations of development and block land
- Valuation of specialist property under depreciated replacement cost methodology
- Mass Appraisal Valuation techniques for revaluations
- Financial Reporting and Asset Valuations and Reporting
- Legislation, requirements and procedures for rating valuations
- Procedural and reporting for Land Valuation Tribunal

Kris Vulinovich
Formal Qualifications
- Registered Valuer
- Member of the Property Institute of New Zealand (MPINZ)
- Bachelor of Property - University of Auckland
Industry Experience
Kris is a Registered Valuer and is currently a Regional Director for the New Zealand Residential team. He began his career in the company back in 2004 for Sheldon & Partners Limited after completing a Bachelor of Property at the University of Auckland. Since 2005, Kris has specialised in a broad range of residential valuations within the south Auckland locality and has established strong relationships with local key stakeholders whilst managing his residential team.
Areas of Expertise
Residential Property Valuations for:
- Mortgage requirements
- Selling or pre purchase
- Urban infill redevelopment sites
- Existing and proposed

Joe Holmes
Formal Qualifications
- Certified Practising Valuer
- Associate Member of the Australian Property Institute (API Member No. 82770)
- Registered Valuer (NZIV, MPINZ) (Registration Certificate No. 3942)
- Land Valuers Licence (Western Australia) (Licence No. LV45100)
- Bachelor of Applied Science (Property and Valuation) (1st Class Honours)
Industry Experience
Joe is an experienced rating and taxing valuer having commenced his career in Melbourne undertaking a range of valuations for municipalities including Manningham City Council, Kingston City Council, Glen Eira City Council, Frankston City Council, Yarra City Council, Moreland City Council, Mornington Shire and more. He has vast experience returning annual general revaluations, objections, supplementary valuations, public open space contribution valuations, asset valuations, rental determinations and insurance valuations covering a range of property types such as commercial, industrial, residential, and specialist. In 2020 he migrated home to Auckland (New Zealand) and in 2021 joined Opteon as an Associate Director in their Government and Advisory team. He is a Registered Valuer in New Zealand, Certified Practising Valuer in Victoria, and holds a Land Valuers Licence in Western Australia.
Areas of Expertise
- Valuations for property taxation, legislation and policy purposes
- Mass valuation modelling
- Rating and taxing valuations
- Rating and Land Tax objections
- Asset valuations for financial reporting purposes
- Public open space contribution valuations

Alexander Dolejschka-Ang
Formal Qualifications
- Registered Property Valuer
- Bachelor of Property and Bachelor of Commerce (Econ/Fin) Conjoint – University of Auckland
- IB Diploma
Industry Experience
Alex has been working with Opteon since 2021, following four years’ experience in the field and earning his valuation registration in 2020. In his previous role, Alex worked on broad range of valuations, including commercial/industrial, residential, land development, rent reviews, and insurance valuations.
Since joining Opteon, Alex’s focus has been on residential valuations predominantly in the South Auckland market, and lifestyle valuations in the Rodney district including Coatesville. Alex is heavily engaged with the property valuation industry, serving as the Treasurer of the Property Institute of Auckland branch for the last four years.
Areas of Expertise
- Residential property valuations
- As If Complete, Kiwibuild, Land and development valuations
- Valuations for mortgage security, relationship property purposes
- Valuations for pre-purchase / pre-sale advice
- Insurance valuations, rent reviews, commercial/industrial valuations

Ben Williams
Formal Qualifications
- BProp (UoA)
Industry Experience
Ben has been with Opteon for eight months after completing his Bachelor of Property with the University of Auckland in 2022. He has assisted in the successful completion of roll maintenance deadlines having gained experience in residential, rural and lifestyle valuations.
Areas of Expertise
Throughout Ben’s time with Opteon, he has been building his expertise in residential and lifestyle valuations.

Brian Stafford-Bush
Formal Qualifications
- Registered Property Valuer
- Fellow of the New Zealand Institute of Valuers
- Fellow of the Property Institute of New Zealand
- Bachelor of Science
- Diploma in Business and Industrial Administration
Industry Experience
Brian has been working as a valuer for over 35 years, formerly as part owner of Sheldon and Partners, now consultant to Opteon. He is viewed as one of the profession’s “wise old heads” a sounding board and go to person to solve valuation problems. He has mentored and trained a number of younger valuers with his expertise covering a wide range of property types and issues.
Areas of Expertise
- Compensation under the Public Works Act
- Insurance valuations
- Commercial/Industrial market values for purchase, sale, finance
- Commercial/industrial rentals
- Ownership transfers for Trusts, Taxation, matrimonial
- Specialist properties such as childcare centers and private schools

Ewen Lilburn
Formal Qualifications
- New Zealand Certificate in Engineering
- Bachelor of Business Studies (Massey University - ongoing)
Industry Experience
Ewen has over 15 years’ experience in the property valuation industry, primarily with Government services throughout the Northland region. He is proficient in residential, lifestyle and rural valuation techniques required in the maintenance of the District Valuation Roll and has an in depth knowledge of legislation that impacts rating valuation methodology.
Ewen provides specialist expertise in index creation and statistical interpretation of mass appraised data gleaned from the successful implementation of fourteen district revaluation projects. Ewen’s engineering background brings to Opteon added knowledge of data integrity techniques and the ability to streamline workflow processes for accurate outcomes.
Areas of Expertise
- Residential and lifestyle property valuations
- District Revaluations
- Mass valuation modelling
- Territorial Authority account management
- Asset valuation for private and government clients

Gary Brunsdon
Formal Qualifications
- ANZIV, SPINZ
Industry Experience
Gary began his valuation career in 1978 under a valuation cadetship with Valuation New Zealand, while completing a Diploma in Valuation at Auckland University. After qualifying in 1981 Gary obtained registration in 1983. Gary is now a Senior Member of the Property Institute and an Associate of the New Zealand Institute of Valuers.
He joined Sheldons in 1987, and then became a director of Sheldons in 1992. On a day to day basis, he was responsible for the residential side of the Company involved in staff training, the joint directorship of the practice and overseeing the daily administration of Sheldons. Following the recent rebranding to Opteon New Zealand Limited Gary has stepped back from a full-time management role and now fulfills a consultancy role including mentoring of the younger team members.
Areas of Expertise
Gary specialises in residential valuations on the North Shore covering Albany, Hillcrest, Birkenhead, Northcote and Glenfield.

James Clark
Formal Qualifications
- Senior Member of the Property Institute of New Zealand (SPINZ)
- Associate of the Institute of Valuers (ANZIV)
- Registered Valuer – Registration Certificate Number – 2757
- Bachelor of Property Administration (BPA) from the Auckland University
Industry Experience
James began his valuation career in 1986 under a valuation cadetship with Housing New Zealand (formerly Housing Corporation of NZ), where he received practical experience in the building and valuation industry, property management and general administration. He obtained a Bachelor of Property Administration and is a Senior member of the Property Institute of New Zealand and an Associate Member of The New Zealand Institute of Valuers.
James practised in Whangarei for 9 years covering a wide range of valuation work from commercial/industrial through to residential and small blocks, before moving to Auckland in 1992 and continuing to value within the wider Isthmus. He joined Sheldon & Partners in 2001 and specialises in residential valuations within the Eastern suburbs where he resides, with particular interest in higher priced property. This encompasses the Central Bays area from Parnell to St Heliers, Glendowie, Panmure, Ellerslie, Mt Wellington and Remuera. James has an extensive client base and is one of the more experienced residential valuers in the Central Bays.
Areas of Expertise
- Residential Valuations
- Mortgage Security purposes
- Pre-purchase
- Pre-sale
- Development
- Trust formation

Jason Wong
Formal Qualifications
- Registered Valuer
- Member of the Property Institute of New Zealand
- Bachelor of Property, Auckland University
Industry Experience
Jason started with Sheldon & Partners (later acquired by Opteon Solutions) in 2007 starting in the West Auckland residential team before transitioning in 2009 to the commercial team working predominantly under Brian Stafford-Bush where he has completed a variety of work throughout Auckland. Following registration in 2015, Jason has focused on the South Auckland Commercial Industrial market, including work on a wide range of insurance valuations and helping with the training of Graduate Valuers within the firm.
From 2014 to 2016 Jason also served on the Auckland Branch Committee for The Property Institute of New Zealand serving as CPD Conveyor organising a variety of educational events for the membership.
Areas of Expertise
- Commercial/Industrial Valuations with a focus on South Auckland
- Insurance Valuations, in particularly Bodies Corporate
- Assessments relating to the Unit Titles Act including Ownership Interest and Utility Interest assessments
%20Qin.jpg)
Jeffrey Qin
Formal Qualifications
- Registered Valuer Licence No. 3852
- Member of the Property Institute of New Zealand
- Bachelor of Property, Auckland University, New Zealand – 2012
Industry Experience
In 2019 Jeffrey became a Registered Property Valuer. Jeffrey started working at Opteon in 2014 as a commercial valuer undertaking a range of commercial and industrial valuations in the central Auckland region. Over the last few years Jeffrey has focused on residential and development land valuations within the south and central Auckland regions being involved in a wide spectrum of valuation assignments ranging from standard residential properties to high value complex assets and subdivision projects.
Areas of Expertise
- Residential valuations
- Commercial & Industrial valuations
- Development Land valuations
- Mortgage requirements
- Pre-sale and pre-purchase advice
- Insurance valuations

Jessie Jiang
Formal Qualifications
- Registered Valuer (NZ)
- Associate Member of the New Zealand Institute of Valuers
- Member of the Property Institute of New Zealand
- Bachelor of Property, Auckland University
- LLB (Peking University)
Industry Experience
Jessie began her valuation career in early 1999, gaining a wide range of valuation experience, involved in various consultancy assignments including site acquisition and disposal, financial analysis in conjunction with leasing and development projects, budget analysis in portfolio management and cell site acquisitions for the communication network. After joining Sheldons in 2002, Jessie specialised in residential valuations. Wanting to expand her commercial experience Jessie worked as a senior valuer for Bayleys Valuations Limited in 2004-2005. Her main focus was commercial and industrial valuations including market valuations, rental reviews, arbitrations and compulsory acquisitions. In 2006, Jessie joined Jones Lang LaSalle (JLL) where she was responsible for commercial valuations including office buildings, shopping centres, large blocks of land and industrial properties. In 2007, Jessie re-joined Sheldons to fulfil the role of commercial team leader and shareholding director. After Sheldon’s rebranding to Opteon, she is now an Associate Director with Opteon New Zealand.
Areas of Expertise
- Commercial and Industrial valuations
- Development valuations
- Asset valuations for financial reporting purposes
- Valuation for mortgage security purposes
- General Property Consultancy
- Insurance valuations
- Rental valuations

John Hickey
Formal Qualifications
- Registered Valuer
- Associate of the New Zealand Institute of Valuers
- Senior Member of the New Zealand Property Institute
- Diploma in Urban Valuation from Auckland University
Industry Experience
John is highly regarded as a valuer and is very experienced in the areas he concentrates on being Auckland’s Eastern and far Eastern Suburbs.
Areas of Expertise
- Residential property valuations
- Valuations for mortgage security purposes
- Valuations for property taxation purposes
- Valuations for pre-purchase/pre-sale advice purposes
- Valuations for compensation purposes
- Valuations for insurance purposes
- Rental valuations

Leeane Gregory
Formal Qualifications
- Registered Valuer
- Member of the Property Institute New Zealand (PINZ)
- Bachelor of Property (University of Auckland 2003)
- Bachelor of Commerce (BGS) (University of Auckland 2008)
Industry Experience
Leeane joined Opteon NZ in 2016, having previously worked for Sheldon and Partners, CBRE and Aim Valuation from 2003. She has a range of expertise with specific focus in residential property, including valuation of single and multi-dwelling residential properties, apartments, investment property, land and development land, construction, insurance and high value residential property within the Auckland Area. Leeane also provides reports to councils and government departments for specialised purposes, including for acquisition and disposal requirements, rental and development assessments amongst others.
Areas of Expertise
Residential Property Valuations for:
- Residential property valuations
- Development land and construction (including progress payment certificates)
- Valuations for mortgage security purposes (including apartments and high value properties, multiple income units and investment properties)
- Valuations for property taxation, legislation, acquisition including partial acquisition
- Valuations for pre-purchase / pre-sale advice purposes / division of relationship and estate property
- Asset valuations for financial reporting purposes
- Valuation for insurance certificates
- Rental assessment

Mark Davidson
Formal Qualifications
- Registered Valuer
- Member of the Property Institute of New Zealand
- Bachelor of Property, Auckland University
- Diploma of eCommerce
Industry Experience
Mark joined Opteon in 2017. He graduated from Auckland University in 1997 with a Bachelor of Property and worked as a valuer before heading overseas for several years. More recently Mark has worked in residential development management, construction and project management roles before returning to valuation. He has been a keen property investor since 2008 and enjoys the nature of the ever-changing market. Mark is currently a member of the Commercial & Industrial team with a focus on the North Shore & Rodney markets.
Areas of Expertise
- Commercial & industrial valuations
- Pre-sale and pre-purchase advice
- Rental assessments
- Insurance valuations
- Tax depreciation valuations
- Subdivisional/development land valuations
- Asset valuations for financial reporting
- Development feasibility

Mark Grinlinton
Formal Qualifications
- B Com Ag (Valuation & Farm Management), 1984.
- Registered Valuer, 1987.
- Associate status of the New Zealand Institute of Valuers, 1989.
- Senior member of the Property Institute of New Zealand, 2005.
Industry Experience
Mark has been responsible for the delivery of over 30 revaluations since 1999 and held leading valuation positions with Valuation NZ, QV, Landmass and Opteon. He began his valuation career in 1984 in the Gisborne office of Valuation NZ. In 1989 he moved to Tauranga and held the position of Rating Valuation Manager for Quotable Value from 1999 to 2004. From 2004 to 2015 he was a director and shareholder of Landmass Technology, until its purchase by Opteon where he held the positions of General Manager Government Services and Rural Director until early 2019. Following a brief absence, he has returned to add his significant experience and assist Opteon in his role as Registered Property Valuer.
Mark has been a Registered Valuer specialising in the delivery of rating valuations for most of his 36-year career. This experience has led to a strong understanding and long involvement in the Rating Valuation industry.
Areas of Expertise
- Specialist in all aspects of rural valuations.
- Management roles extending two decades in the successful delivery of Rating Valuation Service Provider contracts.
- Strong understanding of the Rating Valuations Act 1988, associated Rules, the Te Ture Whenua Act 1993 and relevant case law.
- Comprehensive knowledge of the Land Information New Zealand audit requirements.
- Expert witness for Councils on many Land valuation Tribunal hearings, including cases of national importance involving Maori land and forestry.
- Member of the expert committee that reviewed the 2008 Rating Valuation Rules.

Martyn Oostveen
Formal Qualifications
- Bachelor of Commerce (Agriculture) Majoring in Rural Valuation and Farm Management from Lincoln University.
- Full Member of Property Institute (MPINZ)
Industry Experience
Martyn is an experienced rating valuer and has been with Opteon for almost 5 years and during this time has participated and managed several revaluations. His experience extends to dairy, pastoral, lifestyle and residential valuations. Martyn prides himself in his knowledge in rating valuation legislation and the quality assurance of valuations and data. Martyn is working towards becoming a registered valuer in late 2020/2021.
Before valuation career, Martyn worked on a dairy farm employed as a manager.
Areas of Expertise
- Rural valuation
- Mass Ad hoc modelling within Valor database
- Mass indexing
- Rating legislation
- Management of valuers and rating staff
- Revaluation and maintenance audits
- General technology
- District valuation roll computer systems

Mate Finlay
Formal Qualifications
• Bachelor of Property (University of Auckland) 2016 - 2019
Industry Experience
Mate graduated from University of Auckland in March 2020, where he completed a Bachelor of Property. On completion of his degree, Mate joined the Auckland Council as a Graduate Valuer where he conducted Rating Valuations across the Auckland property market. Mate joined Opteon in October 2020 where he has since moved his existing experience to conducting Rating Valuations in Hamilton’s property market. Mate has undertaken variations of valuations including building consents, subdivisions, amalgamations of titles and owner objections.
Areas of Expertise
• Preparing valuations for rating purposes (Including in both the Auckland and Hamilton market)

Michael Dempsey
Formal Qualifications
- Licensed Valuer in Auckland, New Zealand Registration Certificate No.3879
- Member of the Property Institute New Zealand
- Practising Certificate No. 843
- Bachelor of Business Studies (Valuation and Property Management) - Massey University, New Zealand (2015)
Industry Experience
In 2019 Michael became a Registered Property Valuer in New Zealand with three years prior valuation experience in Auckland and as a member of the New Zealand Property Institute.
Michael’s experience includes the preparation of Valuations and consultancy advice for residential asset classes ranging from prestige residences to urban infill redevelopment sites, existing and proposed residential.
Areas of Expertise
- Residential valuations
- Mortgage requirements
- Strategic investment property advice
- Resumption of freehold land
- Pre-sale and pre-purchase advice

Ming Zhao
Formal Qualifications
- Bachelor of Property & Bachelor of Commerce (Conjoint Degree) from the University of Auckland
- Registered Valuer – 2011 Registration Certificate No. 3605
Industry Experience
Ming is currently working as a senior residential valuer. He joined Sheldon & Partners Limited in 2003 as a valuer while he completed his studies at the University of Auckland. Ming started full time in 2005 after completing his Bachelor of Property and Bachelor of Commerce degrees. He went on to gain registration as a valuer in 2011.
Ming has firmly established himself as a highly regarded apartment specialist with his expertise including a broad range of apartment valuations such as leaky building/leasehold/serviced apartment valuations, etc. in Auckland City and fringe city suburbs. Ming’s expertise also includes residential valuations in the central Auckland area, such as Blockhouse Bay, New Windsor, Lynfield and Mt Roskill. Ming is bilingual in Mandarin and Cantonese and his valuation expertise is predominantly residential.
Areas of Expertise
- Residential property valuations
- Broad range of Apartment valuations including freehold/leasehold/serviced/leaky building/rental valuations
- Valuation for mortgage security purposes
- Valuation for property taxation, legislation and disclosure purposes
- Pre-sale and pre-purchase advice
- Rental Assessments
- Subdivisional/development land valuations
- Development feasibility

Ryan Thomson
Formal Qualifications
- Bachelor of Business Studies Majoring in (Valuation and Property Management) completed at Massey University, Albany, Auckland - 2015
- Member of the New Zealand Property Institute
- Registered Valuer License No. 3880
Industry Experience
In August 2019 Ryan became a Registered Property valuer in New Zealand with four and a half years prior valuation experience in Auckland as member of the New Zealand Property Institute. Ryan has worked at Opteon (formerly Sheldons) since May 2014, with his main area of work being as a commercial and industrial valuer throughout South Auckland and this year mainly concentrating on residential work.
Ryan is now working towards gaining ANZIV solely undertaking residential work throughout Hamilton and South Auckland. Having grown up and attended all his schooling in Hamilton before shifting to Auckland for University, Ryan has in depth knowledge of Hamilton and the wider Waikato Region.
Ryan’s experience includes the preparation of Valuations for a wide range of residential, commercial and industrial properties.
Areas of Expertise
- Residential and commercial valuations
- Mortgage requirements
- Asset valuations for financial reporting
- Insurance valuations

Shelley Manson
Formal Qualification
- Bachelor of Business Studies (Valuation and Property Management)
- Massey University, Manawatu, New Zealand, 1995
- Member of the Property Institute of New Zealand and Friend of the Property Foundation Massey University
Industry Experience
Shelley joined Opteon NZ in early 2021 after returning to New Zealand with her family. She is undertaking residential and rural rating valuations within Western Bay of Plenty, Tauranga City, South Waikato, Rotorua and Taupo District Councils.
Hailing from rural Bay of Plenty and having gained early valuation experience with a provincial firm in Rotorua, Shelley looks to combine her subsequent experience in administration, finance and customer service roles to develop her career and work towards registration.
Areas of Expertise
- Valuations for ratings purposes
- Valuations for Mortgage purposes
- Client relations
- Rural and hospitality sectors

Simon-Peter Finlay
Formal Qualifications
- Bachelor of Property – University of Auckland
- Member of the NZ Institute of Valuers and Property Institute NZ
Industry Experience
Simon-Peter graduated from Auckland University in March 2013, where he completed a Bachelor of Property. Upon completion of his degree, he joined Sheldons (now Opteon) and specialised in residential valuations within the South and West Auckland areas. In early 2018 Simon-Peter established the Opteon brand in the Waikato region, and now specialises in residential valuations in Hamilton and its surrounding districts.
Areas of Expertise
- Preparing residential valuations for mortgage purposes (including valuations for the Corelogic and Valocity panels)
- Preparing lifestyle valuations for mortgage purposes (including valuations for Corelogic and Valocity panels)
- Preparing insurance valuations for Body Corporates and residential homes

Tom Mabbott
Formal Qualifications
- BProp (UoA)
Industry Experience
Tom has been with Opteon for two-years after completing his Bachelor of Property with the University of Auckland in 2018. He has assisted in the successful completion of revaluations and roll maintenance deadlines having gained experience in residential, rural and lifestyle valuations.
Areas of Expertise
The majority of Tom’s time with Opteon he has been working on residential valuations so his expertise lays here.

Tony Mcewan
Formal Qualifications
- Registered Valuer
- Fellow of the New Zealand Institute of Valuers
- Fellow of the Property Institute of New Zealand
Industry Experience
Tony began his career as a valuer in 1974 with Valuation New Zealand and has worked as a full-time valuer for over 40-years. Tony is a founding Director of Sheldons and now a consultant, contractor to the company, which has now been rebranded as Opteon New Zealand Ltd.
He is a past Chairman of the Auckland Branch of The New Zealand Institute of Valuers and New Zealand Property Institute and was admitted as a Fellow of those Institutes in 2002 in recognition of my services to the profession and expertise as a Valuer.
Most of his experience has been in the greater Auckland Region. He has previously been employed in Northland and has provided services for clients in various regional centres in the North Island.

Danielle Nikora
Formal Qualifications
-
Bachelor of Business Property (Ongoing) - Massey University
-
National Certificate in Real Estate – Salesperson - The Skills Organisation
-
Certificate IV in Property Services – Property Management - Kaplan Institute
Industry Experience
Danielle has several years’ experience in the property industry, including property management, property sales, and business development. She is currently working towards a Bachelor of Business (Property) with the goal of becoming a Registered Valuer.
Areas of Expertise
- Valuations for rating purposes
- Market analysis

Chris Knight
MBA, M BUS (PROP), AAPI CPV, MRICS
Chris is the Group Chief Executive Officer of Opteon’s global operations. Chris has been with Opteon since 2006, and, prior to Opteon’s integration, was previously CEO of the largest member firm.
During his time as CEO, Chris has led the Opteon team in successfully transitioning to a new business model, including the acquisition of 17-member firms resulting in the integration of 90% of the total revenue into a wholly owned company, along with 3 other acquisitions throughout Australia and New Zealand.
He is currently executing an ambitious business plan for Opteon designed to deliver further growth through organic means, strategic acquisitions into other non-property sectors, and international expansion.
Chris is focused on consolidating Opteon’s position as a technology leader through innovation, particularly in the areas of property technology, professional services software solutions and diversifying business and product lines.
Chris has qualifications in Accounting, Real Estate, Valuations, a Master of Business (Property) and Master of Business Administration (MBA). He is a Certified Practicing Valuer with the Australian Property Institute (API), a member of the Royal Institution of Chartered Surveyors (RICS) and more recently an API Board Director since May 2018.

Johan Wikman
Johan joined Opteon in October 2022 as Chief Technology Officer and is responsible for the company’s products and technology. Johan has over 20 years’ experience in leading high performing software engineering teams.
Prior to joining Opteon, he spent 10 years at Appen leading the engineering team as CTO and VP of Engineering implementing technologies that evolved the company from a service to a tech led business. During his time on the executive team, the company experienced revenue growth of more than 1,400%, the engineering team grew from 3 people to over 100 and he was part of the team that took the company public in 2015.
In 2010, Johan founded Kontribune, an online publishing platform for communities to share and inspire through the power of story, which was acquired by Appen in 2012. Before that, he was founder and co-founder of multiple startups leading the development of technology teams in B to C and B to B solution. His career also includes engineering leadership roles at Autodesk, Zynga and Lithium.
Johan spent his formative years in Stockholm, Sweden before locating to the San Francisco Bay Area.

Lisa Billington
Lisa commenced with Opteon in 2016, playing an important role in Opteon’s transformation to an integrated structure in early 2017, and Opteon’s 27 acquisitions since her commencement.
Lisa is responsible for Opteon’s global legal, risk, compliance, quality and secretariat functions, leading a team of 25 professionals to support Opteon’s strategy and growth in a way that balances opportunities with risk.
Lisa is a senior corporate lawyer with significant experience across a wide range of areas including mergers & acquisitions, corporate governance and general commercial law. Prior to joining the Opteon team, Lisa worked at law firms Clayton Utz and Maddocks and in-house for an education and media company.
Lisa holds a current legal practising certificate, a Bachelor of Laws (Hons) and Bachelor of Science (Hons) from the University of Melbourne and has completed the Governance Institute of Australia’s Certificate of Governance Practice. She was included in Australasian Lawyer’s 2022 in-house leaders list.

Scott Chapman
AAPI CPV
With many years’ experience establishing and leading large-scale businesses, Scott has significant expertise across the property sector with a career spanning over 20 years in the broader property industry and 14 years within valuations.
With a proven track record of strategy execution, building high performing teams and delivering business growth in complex environments, Scott brings a breadth of expertise across the end to end business value chain including sales, client relationship and account management, leading projects, customer service delivery and product development.
Scott has been with Opteon since 2009 and holds an MBA from Deakin University and a Masters in Property (Valuations) from RMIT.

James Harkness
James was appointed Chief Financial Officer in December 2017. James leads financial strategy, reporting, analysis, compliance and advice across Opteon.
James has a proven track record engaging with progressive leaders who thrive on delivering results in high growth businesses.
With a combination of financial, commercial and operational experience, James contributes to Opteon’s leadership through developing and executing financial, commercial, cost leadership, operational efficiency and people development strategies.
Before joining Opteon, James was Chief Financial Officer at the ASX listed Capital Health Limited, and held senior executive roles at CareerOne, Jetstar, Nu Energy and Acciona.
James is a qualified Chartered Accountant, graduate of the Australian Institute of Company Directors and holds a Bachelor of Commerce from the University of Melbourne.
Request a Quote
Ready to get started? Follow the link below to fill out a quote request and an Opteon team member will be in touch shortly.
Get Started