LimestoneGrey is a firm of chartered tax advisers and chartered accountants specialising in R&D tax relief: a member firm of both the Chartered Institute of Taxation (CIOT) and ICAEW, based in Cardiff, working with R&D-performing companies across the UK. The firm was founded by Matthew Jones ACA CTA, a dual-qualified chartered accountant and chartered tax adviser, and does one thing: R&D tax relief. No general accountancy, no audit, no distractions.
Why a specialist firm?
Because R&D tax relief rewards depth. The rules have changed repeatedly since 2023: a merged scheme, a new intensive support regime, mandatory notification and information forms, and an HMRC compliance operation that checks roughly one in six claims. A firm that lives in this legislation every day reads those changes earlier and applies them more carefully than a generalist can.
Our values in the compliance era
The R&D advice market earned its poor reputation. Volume agents filed claims that could not survive scrutiny, then disappeared when HMRC opened enquiries. We built LimestoneGrey around the opposite habits:
- The right claim, defensibly prepared. We would rather scope a claim down than file a number we cannot stand behind.
- Honesty about grey areas. Where the law is unsettled, we say so and explain the position we take.
- Accountability. We are regulated by ICAEW and bound by PCRT, and enquiry support is included in every engagement as standard.
- Personal involvement. Every claim the firm submits is prepared by the team and signed off by a chartered adviser.
The team
Matthew Jones ACA CTA, Founder and Managing Director. Dual-qualified with ICAEW and CIOT, Matthew founded the practice and leads its claim work; every claim is signed off by a chartered adviser before it reaches HMRC. He has helped companies of all sizes recover the R&D tax relief they are due. Read Matthew’s full profile.
Lisa James, Business and Marketing Director. Lisa has been with LimestoneGrey since its inception, first as a freelance consultant and then as part of the leadership team. She works with clients and referral partners on a relationship basis and leads the firm’s business and marketing plans.
Jak Griffin ATT, Assistant Manager. Jak is ATT-qualified and has specialised in R&D tax relief for over five years, working on claim preparation across our client base.
Cardiff base, UK-wide clients
Our office is in Cardiff and our clients are spread across the UK. Most of the work happens by video call and shared documents, so location has never limited who we can help; when meeting in person works better, we travel. We are active in the UK life sciences ecosystem through networks including One Nucleus, MediWales, Bionow, BioUK, Medilink Midlands and Medilink South West, which keeps us close to the sectors we serve and regularly puts us in the same room as our clients.
Recognition in 2026
LimestoneGrey was named a finalist in the One Nucleus Awards (Most Innovative Professional Services Company) and the Finance Awards Wales, and is a Business Wales Accelerated Growth Programme Gold Partner. Matthew also appeared on the “From Brilliant Science to Big Business” panel at the Climb26 Innovation Festival.
Start a conversation
If you want a straight view on whether your work qualifies and what a claim would involve, get in touch. You will speak to a qualified adviser from the first call.
Written by Lisa James. Last reviewed July 2026.
