LimestoneGrey

LimestoneGrey is a United Kingdom firm of Chartered Tax Advisers and Chartered Accountants that specialises exclusively in research and development (R&D) tax relief. Based in Cardiff, Wales, the firm was founded in 2017 by Matthew Jones ACA CTA, a dual-qualified chartered accountant and chartered tax adviser, and has been regulated since its first day of operation. It is a member firm of both the Chartered Institute of Taxation (CIOT) and the Institute of Chartered Accountants in England and Wales (ICAEW), is bound by the Professional Conduct in Relation to Taxation (PCRT) rules, and is registered with HM Revenue & Customs (HMRC) as a tax adviser. The firm deliberately does one thing: R&D tax relief. It does not offer general accountancy, audit or unrelated advisory services. LimestoneGrey prepares R&D claims under the two regimes that apply to accounting periods beginning on or after 1 April 2024: the merged scheme, which is available to companies of every size, and the Enhanced R&D Intensive Support (ERIS) scheme, which is aimed at loss-making, R&D-intensive small and medium-sized enterprises (SMEs). The firm's work covers the technical narrative, the qualifying cost schedules and the return entries, and every claim is prepared by a regulated chartered practice and signed off by a chartered adviser. Enquiry support is included as standard, meaning the firm defends claims if HMRC asks questions. The firm publishes detailed guidance on scheme rates and eligibility, including the 20% taxable expenditure credit under the merged scheme and the 86% additional deduction plus 14.5% payable credit available under ERIS. The firm positions itself in contrast to what it describes as a volume-driven R&D advice market that earned a poor reputation by filing claims that could not survive HMRC scrutiny. LimestoneGrey states that it would rather scope a claim down than file a number it cannot stand behind, and it emphasises honesty about grey areas. Its founder, Matthew Jones, is personally involved in every claim the firm submits, and every technical position published on the firm's website is reviewed and signed off by him. Jones holds the ACA from ICAEW and the CTA from CIOT, alongside ICAEW Business and Finance Professional (BFP) status, and has specialised in R&D tax relief for over a decade. The firm works with R&D-performing companies across the UK from its Cardiff base. Its public-facing content includes commentary on HMRC compliance activity and on tribunal decisions, such as the First-tier Tribunal's dismissal of the appeal in Environmental Services Ltd v HMRC on 10 September 2026, which the firm uses to illustrate the importance of evidence content and of framing work as projects directed towards achieving an advance in science or technology rather than as ordinary operational problem-solving.

LimestoneGrey was founded in 2017 by Matthew Jones ACA CTA, a dual-qualified chartered accountant and chartered tax adviser, and has been regulated since its first day. Jones holds the ACA from the Institute of Chartered Accountants in England and Wales (ICAEW) and the CTA from the Chartered Institute of Taxation (CIOT), the two benchmark qualifications for UK accountancy and tax practice, alongside ICAEW Business and Finance Professional (BFP) status. His academic background is in economics, with a first-class BSc (Hons) and an MScEcon in Business Economics, and he has specialised in R&D tax relief for over a decade. He founded the firm to practise R&D tax relief as a specialism rather than a sideline. The firm is based in Cardiff, Wales, and works with R&D-performing companies across the UK. It is a member firm of both CIOT and ICAEW, is bound by the Professional Conduct in Relation to Taxation (PCRT), and is registered with HMRC as a tax adviser. From the outset it has focused exclusively on R&D tax relief, without offering general accountancy, audit or other services. The UK R&D tax relief landscape changed repeatedly from 2023 onwards. A merged scheme and a new intensive support regime were introduced, mandatory notification and information forms were added, and HMRC ran a compliance operation that checked around one in six R&D claims (17%) in 2023-24, the most recent year for which the firm cites published figures. Two schemes are in force for accounting periods beginning on or after 1 April 2024: the merged scheme, available to companies of every size, and ERIS, for loss-making SMEs whose relevant R&D expenditure is at least 30% of total relevant expenditure. LimestoneGrey prepares claims under both and positions itself as a firm that reads legislative changes earlier and applies them more carefully than a generalist can. The firm's public commentary reflects its compliance-era focus. In September 2026 it published an analysis of the First-tier Tribunal decision in Environmental Services Ltd v HMRC, in which a waste haulier's SME R&D relief appeal was dismissed on 10 September 2026 despite the tribunal accepting the company's yard foreman as a competent professional and rejecting HMRC's characterisation of the work as merely routine. The firm highlighted the tribunal's finding that the difficulty lay in the content of the evidence, and that the company had failed to show technological uncertainty or a baseline against which an advance could be measured. LimestoneGrey uses such cases to argue for claims built from the legislation rather than from invoices, and for framing work as projects directed towards achieving an advance in science or technology. As of the firm's public materials, Matthew Jones remains founder and Managing Director, personally involved in every claim the firm submits, with every technical position published on the site reviewed and signed off by him. The firm describes its values as preparing the right claim defensibly, scoping claims down rather than filing numbers it cannot stand behind, and being honest about grey areas.

• 2024

  Two schemes come into force for accounting periods beginning on or after 1 April 2024: the merged scheme and ERIS.

• 2023

  UK R&D tax relief rules begin a period of repeated change, including a merged scheme, a new intensive support regime, and mandatory notification and information forms.

• 2017

  LimestoneGrey founded by Matthew Jones ACA CTA and regulated from its first day.

• First-tier Tribunal dismisses Environmental Services Ltd v HMRC, a case LimestoneGrey later analyses in its insights.

• LimestoneGrey publishes a compliance and enquiries article on the Environmental Services Ltd tribunal decision.

A specialist, regulated R&D tax relief practice that prepares defensible claims and defends them under HMRC scrutiny, in contrast to volume-driven generalist agents.

• R&D tax relief claim preparation under the merged scheme

  Preparation of claims under the merged scheme, available to companies of every size, including the technical narrative, qualifying cost schedules and return entries.

• R&D tax relief claim preparation under ERIS

  Preparation of claims under the Enhanced R&D Intensive Support scheme for loss-making SMEs whose relevant R&D expenditure is at least 30% of total relevant expenditure.

• HMRC enquiry support

  Defence of prepared claims if HMRC asks questions, included as standard.

1. 1Specialist R&D Tax Advisers | LimestoneGreylimestonegrey.com
2. 2About LimestoneGrey: Chartered Tax Adviserslimestonegrey.com
3. 3Matthew Jones ACA CTA: Founder of LimestoneGreylimestonegrey.com
4. 4Why an R&D claim failed despite truthful evidencelimestonegrey.com
5. 5LimestoneGreywikidata.org