It’s 2024. Bonham and Brook were hosting a property event at MIPIM in Cannes when IIL approached us to say that we were the preferred partner to take on their client base. Seeing the calibre of the client base, we were immediately interested. One of the main drivers for the situation was that the demands of dealing with HMRC’s new tough stance on compliance meant lengthy and onerous compliance processes that were putting strain on smaller providers. To offer a full service required heavy investment, and seeing numerous ex-HMRC staff on Bonham and Brook’s team gave IIL the comfort that their clients would be in safe hands, which for them took precedence over their own business interests.
A few months later, whilst lawyers were still fine-tuning terms, Dom and Nick decided that they trusted each other enough to start the merger early. That set the tone for two like-minded firms coming together with a shared focus on doing things properly – through expert advice, strong client relationships, and compliant services. With IIL’s strong track record of satisfied clients and Bonham & Brook’s specialist knowledge, the decision to acquire IIL was a no-brainer. Ultimately this was a partnership formed with the common goal of building lasting trust & offering greater value to our clients in a rapidly changing landscape.
Nick Grimond, CEO of IIL and now Partner at Bonham & Brook, recalls the early conversations:
“When we started thinking about a sale, we were focused on finding a partner who really prioritised compliance and client care. The R&D markets has changed so much, and we needed more firepower to keep delivering for our clients. Bonham & Brook had the compliance reputation we were seeking and they exceeded our expectations.”
From day one, both teams were clear: this was about integration, not just acquisition. The goal was to keep what made each business special and combine the best of both. “We didn’t want anyone to feel like they were being taken over. The idea was always to merge strengths and move forward together,” says Dom Bonham, Director of Operations.
The approach paid off. Over the past twelve months, the numbers have exceeded even our own expectations – around £700k delivered in claims, retention of over 90% of the IIL client base, and a strong record on HMRC inquiries, with every single one since January resolved in our clients’ favour. “Having a team that includes ex-HMRC inspectors has really set us apart from most of the rest of the market” says Dom. “It gives our clients and partners an extra level of confidence.”
Nick adds, “We wanted this to be a place where people felt valued and could progress, and that’s exactly what’s happened. The culture’s been a great fit, and everyone’s brought something new to the table.”
The integration wasn’t just about client work. Bringing talented people like Oliver Mountford, Senior Financial Consultant & Compliance Lead, over to Bonham & Brook has helped the whole team level up. Ollie remarks on the success of the merger, from a personal and professional standpoint, “The merger has proven to be a great opportunity for growth – I’ve been able to expand my knowledge across key areas such as R&D, compliance, and partnerships, gaining exposure to areas of work I may not have encountered otherwise.”
“There’s incredible momentum going into the next year. We’re set to deliver more than £1.2 million in claims, with a strong pipeline of new business. Even more importantly, clients are sticking with us and, in many cases, have signed up for multi-year relationships, something that speaks volumes about the trust we’ve built over time, and the firm’s focus on reliable and compliant services.”
For other R&D business owners out there, whether you’re considering your options for the future or just want to see how a partnership might work, we’re always open to a conversation.
Nick, now heading up acquisitions for Bonham & Brook, says it best: “Having been through it myself, I know how big a decision it is. If anyone wants to have an honest, no-pressure chat about the process and what life’s like after a merger, I’d be more than happy to share my experience.”
If you’re curious about what the next chapter could look like for your business, find more information on our range of services and get a free eligibility consultation here > contact us

Director of Operations

Senior Commercial Consultant