LimestoneGrey is a firm of chartered tax advisers and chartered accountants specialising in R&D tax relief, working from an office in Cardiff with clients across the UK. One office, one specialism. This page sets out what being a Cardiff firm actually means for a company in Wales, and what it does not.
Where we are, and why that is worth saying
Our office is at 15 Neptune Court, Vanguard Way, Cardiff CF24 5PJ. It is the firm’s only office, and it is a place you can visit.
That is worth stating plainly, because search results for R&D tax relief in Cardiff are thick with pages from national operators whose presence here begins and ends with the page itself. A city name in a title tag is not an office. The questions worth asking any adviser who claims to be local are ordinary ones: is there a street address, and will the person who answers the phone be involved in your claim?
Here the answer is straightforward. Matthew Jones ACA CTA founded the firm in Cardiff in 2017 and still leads its claim work: your first conversation is with a qualified adviser, the team you meet is the team that prepares the claim, and every claim the firm submits is signed off by a chartered adviser before it reaches HMRC. There is no delivery team your work gets passed down to. Most work runs on video calls and shared documents, which is why the office has never limited who we can help, but when a meeting in person is the better way to do something, we do that.
What a regulated firm on your doorstep is for
LimestoneGrey is a member firm of both the Chartered Institute of Taxation and ICAEW, regulated by ICAEW, bound by PCRT, supervised by ICAEW for anti-money laundering and registered with HMRC as a tax adviser. Those are checkable facts rather than claims about ourselves, and regulation and professional standards explains what each layer means in practice, including the independent complaints route to ICAEW if we ever fall short.
It matters more than it did five years ago. HMRC checked around one in six R&D claims in 2023-24, its latest published figure, and when a claim fails, the consequences land on the company’s directors rather than on the agent who filed it. Enquiry support is included as standard in every LimestoneGrey engagement; HMRC enquiries sets out what that involves.
The Welsh innovation ecosystem we work in
The firm is a Gold Partner of the Business Wales Accelerated Growth Programme, providing in-kind specialist R&D tax support to companies in the programme. In 2026 LimestoneGrey was shortlisted for Independent Accounting Practice of the Year at the Finance Awards Wales and named a finalist at the One Nucleus Awards for Most Innovative Professional Services Company. Matthew appeared on the “From Brilliant Science to Big Business” panel at the Climb26 Innovation Festival.
We are active in MediWales and in the wider UK life sciences networks: One Nucleus, Bionow, BioUK, Medilink Midlands and Medilink South West. That keeps us in the same rooms as the companies we serve rather than reading about them afterwards. We are also members of AberInnovation, whose campus sits at the meeting point of Welsh agri-tech, food and biotech research.
Welsh clients run through the work. Midtec Products, an engineer-led manufacturer in Ammanford, developed a device that retrofits to existing wood-burning stoves and cuts their emissions far enough to meet new DEFRA criteria; the claim delivered a £40,000 benefit across staff, agency and material costs, and the full case study sets out how it was built. Enviro365 first came across us at a Welsh Start Up Convention. Those routes into the client base are not accidents of advertising spend.
Does Wales under-claim R&D tax relief?
Very likely, though the published data is a blunter instrument than the question deserves.
HMRC’s annual statistics split claims by region, and the concentration is stark. Companies registered in London took 24% of claims and 31% of the value in 2023-24, and the South East 15% and 20%. Wales’s row in the same table shows 1,440 claims and £115 million of support — on our own arithmetic from HMRC’s regional table, around 3% of UK claims and 1.5% of the value. Welsh claim volumes fell broadly in line with the UK-wide 26% drop that year, and more than half of Welsh claims come from companies registered in South East Wales.
Two caveats belong with that figure, and most pages selling Welsh R&D services omit both.
The first is that HMRC’s regional split is based on a company’s registered office, and HMRC says openly that a registered office is not necessarily where the R&D happens. A Welsh company registered at its London accountant’s address counts as a London claim. A group with a South East head office counts there, whatever happens at its Bridgend site. The table measures registration, not laboratories.
The second is that the claimant population changed shape rather than simply shrinking. Claims fell 26% to 46,950 in 2023-24 while the qualifying expenditure behind them fell 1%, and the exit was concentrated among smaller and first-time claimants, with claims below £15,000 largely disappearing from the data. Some of those claims should never have been filed. Others were sound claims abandoned because the compliance load started to look heavier than the money. Whether that fell more heavily on Wales than elsewhere is not something the published figures answer, and we are not going to pretend otherwise. Our full reading of the release is in key insights from HMRC’s 2025 R&D statistics.
What we hear in conversations here is more mundane than a policy failure: companies that assume the relief is for people in lab coats, companies whose accountant has never raised it, and first-time claimants who lose a valid claim to the claim notification window, which closes six months after the end of the period of account and invalidates the claim outright when missed.
Serving Wales, and serving the UK
We are a Cardiff firm with clients across the UK, and both halves of that are worth saying. There is no branch network, and we do not pretend to one. The work happens by video call and shared documents, with travel when a meeting genuinely beats a call, and that has been true for clients ten minutes away and clients three hundred miles away alike.
In this field the technical fit matters more than the postcode. What a claim needs is an adviser who can sit with your competent professionals, follow what they did and frame it against the statutory test. The sectors we work in are a better guide to whether we are right for you than a map is.
How to start
A scoping call, half an hour or so. You describe what the company builds and where the technical difficulty sat; we give an honest view on whether it looks like qualifying R&D, which scheme applies and what a claim would involve. If we do not think you should claim, we say so on that call. If you go ahead, the fee is agreed before any work starts, as how we work describes.
Call 0330 223 4 223 or send us a message. If you would rather do it face to face, say so when you call and we will arrange it.
Written by Matthew Jones ACA CTA. Last reviewed July 2026.
Sources
- R&D tax credits statistics, September 2025 — the regional analysis (table RD5: Wales 1,440 claims, £115m), the London and South East concentration, and HMRC’s caveat that a registered office “may not be where actual R&D activity is carried out”. Welsh percentage shares are our calculation from the published absolutes; HMRC publishes none by region.
- HMRC’s approach to R&D tax reliefs 2023–24 — around one in six claims checked in 2023-24.
