LimestoneGrey is a member firm of both the Chartered Institute of Taxation (CIOT) and the Institute of Chartered Accountants in England and Wales (ICAEW): a firm of chartered tax advisers that is also a firm of chartered accountants. We are regulated by ICAEW, bound by Professional Conduct in Relation to Taxation (PCRT), supervised by ICAEW for anti-money laundering, and registered with HMRC as a tax adviser. Much of the damage done in the R&D mis-selling era was done by firms subject to none of these. This page explains what each layer means for you as a client.
What does being a CIOT member firm mean?
The Chartered Institute of Taxation is the leading professional body in the UK for tax advisers, and the CTA qualification it awards is the benchmark for UK tax practice. As a CIOT member firm, our tax advice is given under the Institute’s professional rules and PCRT. That matters here because R&D tax relief is tax law before it is anything else: the definition of qualifying R&D, the cost categories, the procedural requirements and the enquiry process all come from statute and guidance, and we read them as chartered tax advisers first.
What does ICAEW regulation mean for you?
It means the firm answers to a professional body, not just to its own marketing. As an ICAEW-regulated firm we are subject to the Institute’s professional standards and disciplinary framework, our anti-money-laundering compliance is supervised by ICAEW, and there is an independent route for complaints if we ever fall short. Our founder, Matthew Jones ACA CTA, is a member of both institutes and bound by their codes of conduct; every claim the firm submits is signed off by a chartered adviser.
What is PCRT and why does it matter in R&D claims?
PCRT is the professional code that governs tax advice given by members of the main UK accountancy and tax bodies. For R&D work its practical effect is simple: we may only advise a filing position that has a sustainable basis in law, we must not let a fee incentive shape a technical judgement, and we must correct errors when we find them. An agent outside PCRT can file whatever it thinks HMRC will not notice. We cannot, and would not want to.
Is LimestoneGrey registered with HMRC?
Yes. HMRC registration is now required for tax advisers who interact with HMRC on behalf of clients, with anti-money-laundering supervision a condition of registration. We meet both requirements through our ICAEW regulation. When we file your Additional Information Form and deal with HMRC on your claim, we do so as a registered, supervised adviser named on the submission.
Why are unregulated R&D agents a risk?
Because when a claim goes wrong, the consequences land on the company, not the agent. Your directors are responsible for the accuracy of the return, HMRC checks roughly one in six R&D claims, and an unregulated agent has no professional body to answer to, no PCRT duties and no complaints route. HMRC’s own estimates show why scrutiny tightened: error and fraud in R&D relief ran at 17.6% in 2021-22 before falling to 5.9% in 2024-25 as compliance activity increased. If your current adviser will not defend its work in an HMRC enquiry, that tells you what it thinks of its own claims.
What happens if you have a complaint?
Raise it with Matthew directly and we will deal with it quickly and openly. If you are not satisfied with our response, you can escalate the matter to ICAEW, which independently handles complaints about the firms it regulates. Few R&D agents can offer that second step; we regard it as basic client protection.
Our commitments to every client
- The right claim, defensibly prepared: we file nothing we cannot stand behind.
- Every claim is prepared or reviewed by a chartered adviser before it is submitted.
- The fee is agreed before work starts, with no hidden costs.
- Enquiry support is included as standard.
- Where the law is unsettled, we tell you so and explain the position we take.
- We are open about our methods, including how we use AI in our work.
If these standards match what you are looking for in an adviser, start a conversation with us or read how we work.
Written by Matthew Jones ACA CTA. Last reviewed July 2026.
