I'm in the UK. Buying crypto isn't banned, however trading is. I
You are the owner of the money and I don't know why you have to bend to the bank policies since you are from the UK. Why do you change bank just as Welsh said cause I read that Barclay, Natwest, SCB, RBS, TSB supported crypto related payment.
You can also also open Revolut account if you don't want leave the bank though.