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Independence, Impartiality, and Integrity

Welcome to ExpertQS, provider of construction quantum expert services, expert adviser and expert witness services, building and construction cost expert services, independent expert determination, and dispute resolution services within the building and construction industries.

ExpertQS works with solicitors, lawyers, developers, house builders, land owners, construction professionals, planning professionals, together with private and commercial parties, on a wide range of construction cost and quantum disputes. It also offers expert quantity surveyor and project management services.

The company is operated by director Gary A Bushell, FRICS, MAE, QDR, APAEWE based in Windermere in the northwest of England.

With an established reputation for integrity, independence and impartiality, Gary has over 40 years€™ experience dealing with a broad range of clients across the UK. He successfully acts as expert witness and provides robust dispute resolution services, earning high regard from clients and solicitors as a professional quantity surveyor and construction quantum expert.

You can review Gary’s testimonials on this page and contact him on 01539 443009 or 07989 503707 or email him at

Experience and qualifications

Gary is one of the few expert witnesses in the northwest dedicated to quantity surveying and construction cost issues. He acts as expert for claimants and defendants in connection with quantity surveying disputes, and he specialises in the following areas of practice:

  • Construction quantum expert witness services
    • Acts as expert witness for one or all parties to a dispute, preparing expert reports, and giving oral evidence under cross examination in court and tribunals.
  • Quantity surveying services
    • Provides building and construction cost expert and construction quantum expert advice generally and in connection with development appraisals, and planning economic viability appraisals.
  • Dispute resolution services
    • Acts as expert determiner, expert quantity surveyor, and expert adviser.

Gary is an accredited member (MAE) of The Academy of Experts, and adheres to its codes of practice and guidance. The Academy of Experts is the international centre of excellence for experts, promoting high objective standards. He strongly believes in impartiality, attention to detail, and meeting deadlines on time.

In addition, Gary is a Fellow (FRICS) of the Royal Institution of Chartered Surveyors which is a mark of distinction recognised by other professionals, the construction industry, and the public as denoting the highest standards of success, achievement and expertise in his specialism.

Gary complies with the RICS professional ethical standards which deal with integrity, levels of service, trust, respect and responsibility. He is an accredited member of the RICS Expert Witness Registration Scheme (EWRS) and he uses his experience and expertise to mentor others, including prospective RICS candidates.

Gary has attained the Advanced Professional Award in Expert Witness Evidence accredited by Edexcel to masters level (APAEWE).

Gary is a Qualified Dispute Resolver (QDR), he is a member of The Academy of Experts’ Register of Qualified Expert Determiners.

As managing director of Bushell Raven Ltd up to 2013, Gary built up a quantity surveying practice that continues to prosper under the stewardship of his sons Jon and Ed.

With Gary’s track record, qualifications, and experience, you can be sure of a high quality construction quantum expert witness service with a straightforward but professional approach to dispute resolution.

Please take a look at Gary’s services, articles, testimonials, and case studies. Once you have seen what he can do, call Gary today on 01539 443009 or 07989 503 707. Alternatively you can email him on