Been signed up at Single Bet Calculator since around February, usually on the train home, so this is just my two pence. Stumbled on it after a mate mentioned it, not an ad.
The slots side is pretty big — roughly 4,000 slots last time I counted. Pragmatic Play takes up most of the space, so Sweet Bonanza and the usual suspects are all there. I mostly stick to Play'n GO titles out of pure habit. The one thing that irks me — searching for a specific slot at Single Bet Calculator is more faff than it should be, you often have to scroll.
The live dealer bit is powered by Evolution, so you know what you're getting. Proper human dealers, no lag issues on my broadband, and Crazy Time and Lightning Roulette is where I lose most of my money, honestly. Fair to note the UK tables are properly staffed in the evenings. If you want to compare the current terms I'd have a nose at <a>Patent calculator overview and options</a> since the offers shift about.
Bonus-wise at Single Bet Calculator was ?100 matched plus 100 spins on Book of Dead. Rollover is 35x which is standard-ish. They also ran a small no deposit thing when I registered. ?10 minimum, same as everywhere, the form was short enough, ID check was same-day.
Withdrawals are decent. Debit card take 2-3 days, Skrill came through in under 12 hours, and crypto is quickest if you use it. Pulled ?180 out on Tuesday with no drama. Single Bet Calculator's support answered in about four minutes — actually read my message. They're UKGC licensed, which is the bit I actually check. No standalone app, just the mobile site.