Been following this thread with interest. My conclusion: Trustpilot scores for UK casinos are about as reliable as a chocolate teapot.
Stick to UKGC licensed sites, check recent complaints data, test with small amounts first. Everything else is just noise designed to separate you from your money faster.
Bottom line for me - tried it, won some, lost some, got paid when I won. Would I recommend it to my mum? Probably not. Would I use it again? Yeah, probably.