I don't know anything about the accounts, but I know it ain't easy to get one at Barclays. I tried all 3 branches in Glasgow yesterday. All I can say is oof!
My contract with university accommodation and an official letter from my uni was not enough to prove my address to them. They then suggested I get a TV license for a TV I don't have, a provisional driving license for a car I don't have nor will I need, utility bills which I won't have because it's included in my rent, or a phone bill for a phone I can't get because I don't have a bank account.
Since you say you don't have an address, I'd start with going to various banks and asking questions about their range of accounts and what you'll need to open one.
ETA: I forgot the most important part. One branch also asked if I had a UK credit card for proof as she sat there denying me a bank account. Yes ma'am, because clearly I would have acquired a credit card within the week and a half that I've been here, despite the fact that I'm not sure I technically exist in this country as far as credit goes and also despite my inability to prove to any of you people that I'm worthy of a bank account.
