600 clients, and the questions you can’t Google
Liondaris & Co are certified accountants and tax advisers in Cockfosters, North London. Christos Liondaris founded the practice ten years ago; today it acts for around 600 clients, a mixture of individuals, sole traders, limited companies, trusts and partnerships, with a specialism in property tax. The firm has used GAIN Tax since October 2025.
The practice
We founded the practice about ten years ago. Today we service around 600 clients: a mixture of individuals, sole traders and limited companies, plus a few trusts and partnerships. We specialise in property tax, so landlords with multiple properties, held in a variety of different structures.
And lately the work has changed shape. We’ve got clients moving around the world: Cyprus, Dubai, Brazil. They’ve still got income here in the UK, and it becomes a question of how we structure that. In the last year or two we’ve taken on three complex residency cases. That’s the work we use GAIN Tax for.
What research used to look like
Before, research meant Google, pointing us at the right HMRC manual pages. When that wasn’t good enough we’d go to our subscription research package, which lists everything but makes you work hard to navigate it. I wouldn’t call it the best tool.
I was doing something recently on share dilution: issuing shares, diluting a holding, trying to understand the value shifting provisions. You can’t really find that on Google. GAIN Tax gave me a comprehensive answer: look at this manual, with everything referenced direct to the Taxation Act.
How I actually use it
I’m not in it every day. I use it when I really need assistance with something, when I have to navigate the manuals on ground I don’t cover every week. The big ones this year: the foreign income and gains regime, the temporary repatriation facility for a client bringing funds into the UK, and some complex inheritance tax and capital gains questions.
The feature I’d single out is Improve prompt. I ask the question in layman’s terms, it interprets it and offers a better format. I think it’s fantastic. I did some work on it last week and it gave me the relevant information I needed to advise the client.
Every question I’ve asked it, it’s been very useful.
The ChatGPT problem
Here’s the other side of AI in this job. I’ve had three examples now, from two different clients, where they’ve sent me a ChatGPT conversation: follow these eight steps and you’ll pay no tax whatsoever. And it’s just so incorrect. As advisers it wastes our time, because you then have to walk the client back through all of it.
“GAIN Tax is going to be as accurate as possible because it’s picking legislation up. It’s not making it up.”
What I haven’t used yet
I haven’t used the Client Hub or the document analysis. I actually started on the Client Hub during this interview: pulled a client in from Companies House and began moving a couple of my chats into that client.
And there’s a disguised remuneration case that landed on my desk this morning, three years of accounts from the previous accountant. I might run that through the document analysis and see what it comes up with.
What I’d add
Case law. We had a VAT investigation: a chauffeur business client bought a Rolls-Royce, and the inspector held the client’s repayment while the investigation ran. It took a year of back and forth. We believed the VAT was recoverable, and to show it I had to find five tribunal cases on the issue myself, present them, and argue each element. We won: the client got his £40,000 back.
What I’d want is to upload the investigation documents and have the tool go a step further: summarise what the inspector’s asking, then build the argument. Here’s why it’s recoverable, here’s the case law, here are the elements.
The verdict
Would I tell another tax professional it’s worth trying? Always. 100%. I’ve already pointed a couple of accountant friends at it.
One thing I’d say to the GAIN team, and I mean it as a compliment: keep the accuracy. It’s very accurate at what it does, and I’d rather have that than additional features which are less accurate.
“Would I tell another tax professional it’s worth trying? Always. 100%.”
Liondaris & Co are proactive certified accountants and tax advisers in Cockfosters, North London, working with landlords, property investors, construction businesses, designers and content creators, where business is done differently. liondaris.co.uk
Try it on your next tax question
14-day free trial · No credit card required