Midtec Products manufactures chimney cowls and flue terminals in Ammanford, South Wales. When new DEFRA emissions criteria left owners of existing wood-burning stoves outside the improved standards, Midtec’s engineers developed a device that retrofits to those stoves and substantially reduces harmful emissions. LimestoneGrey identified the qualifying R&D, prepared the calculation and technical report, and handled the submission. The claim delivered a £40,000 R&D tax credit benefit.
The situation
DEFRA published new eco criteria on the clean burning of kiln dried hard wood on domestic stoves, aimed at cutting the harmful emissions generated when the fuel burns. New stoves meet the standards through inbuilt technology. Existing stoves cannot, and the legislation did not require them to. Owners of older stoves were simply left outside the new standard.
Midtec read that gap as an opportunity: a product that brought existing stoves up to the new standards would serve environmentally conscious owners the legislation had passed by. Its engineers, whose work already involved continual product development, set out to build one.
The R&D
The project developed an emissions reduction device capable of being retrofitted to pre-existing solid wood-burning stoves, cutting emissions far enough to meet the new standards. The technical difficulty sat in achieving that reduction on hardware that was never designed for it, and the project presented genuine challenges that took time, effort and money to overcome.
That pattern, a defined technical goal with no ready answer, is what the R&D definition is aimed at: a project seeking an advance through resolving technological uncertainty that a competent professional could not readily resolve. Our guide to what counts as qualifying R&D explains the test in full.
It is worth noting what triggered the work. Legislative change is one of the most reliable prompts for qualifying R&D. Sometimes new rules force a company to change its products or processes; sometimes, as here, they open a gap a company chooses to fill. Either route can put development work squarely inside the relief, which is why a regulatory change in your industry is a good moment to reassess whether you qualify.
How we worked
Midtec had claimed R&D tax credits before, so the team recognised the possibility early. We worked alongside their engineers to establish which aspects of the project met the definition and which costs attached to those activities. From there we prepared the R&D calculation and the technical report supporting the claim, and handled the submission to HMRC.
Three cost categories carried the claim: staff costs for the engineers doing the development work, agency staff brought in to support it, and the materials consumed in the work.
The outcome
The claim delivered a £40,000 R&D tax credit benefit. Trefor Jenkins, Director at Midtec Products, commented:
“We had excellent advice and support from LimestoneGrey in handling the submission of the claim and guiding us through the process.”
Matthew Jones of LimestoneGrey added:
“It was a pleasure working with Trefor and the team at Midtec Products. The passion for their craft and their ability to produce quality solutions for gaps in the marketplace is incredible.”
This claim was prepared under the R&D schemes in force at the time. The rates and rules have since changed: for accounting periods beginning on or after 1 April 2024, claims run through the merged scheme or ERIS, and the compliance requirements are stricter. The character of the work, finding the qualifying R&D inside an engineering project and evidencing it properly, is unchanged.
If a regulatory change has pushed your company into development work, that is exactly the moment to assess whether it qualifies. Talk it through with a chartered adviser, or read how we approach manufacturing claims.
Written by Matthew Jones ACA CTA. Last reviewed July 2026.
Every claim turns on its own facts: a past outcome is not a prediction for your company.