Usually the only reason a casino won’t pay-out without the ID they ask for is that there is a concern over the source of the funding.
could be a simple thing like a mismatch between your registered name and the details on your credit file.
Realistically, the easiest solution is to give them what they asked for. You can argue the rights and wrongs all you want (and I’d tend to agree that many requests are too much, but that’s the licensing, not the casino), but realistically - take a photo of what they want, and you’ll almost certainly have the money within 24 hours. Usually less.
AllBritish are good and trustworthy.
then, once you have your money, close your account if you wish. But remember that every site registered in the UK is going to ask for that info at some point.
Then you’ll be left just with the Curacao-market sites, who will ask for far more info and will be a lot less trustworthy with it.