The rules only apply to bank accounts, and there are still circumstances under which they can be frozen, but "bank just decides you can't have your money" is a lot rarer.

Edit: see Which? who are always good on consumer issues: https://www.which.co.uk/news/2021/09/why-banks-are-freezing-... : alleged suspicious activity; https://www.theguardian.com/business/2020/oct/22/exclusive-h... inactivity

Traditional British solution: a QUANGO and an Ombudsman.