I lived in the UK for a few years and the answer to your questions is that there isn't one.
CoinCorner is the only one and it's terrible. They do a lot of shotgun KYC and always requesting more personal information whenever you try to buy or withdraw.
If you have access to a Euro bank account, I would recommend using a service like Relai in Switzerland (
https://relai.app/), Pocket in Switzerland (
https://pocketbitcoin.com/), and/or Bitcoin 21 in Austria (
https://21bitcoin.app/en)
The best way to buy in the UK is from Bisq and Robo Sats for private purchases.
Gemini, Kraken, and even Coinbase are the best for KYC sats.
If you're anywhere near London, go check out The London Bitcoin Space (
https://x.com/londonbtcspace). They're the best meetup group in London led by London's finest bitcoiners.