When HSBC bought the Midland Bank, the UK government required HSBC to legally relocate here. The current cabinet are craven, but I expect they’d still require this, a deal breaker for Apple.
They don't need the very obsolete technology, obsolete business processes and obsolete management mentality of most existing banks. Much better to start with a greenfield site and acquire customers from there.
Many people would drop their existing bank in a heartbeat if there were a viable modern alternative. Apple is in a perfect position to capitalize on this widespread dissatisfaction.
Depends if you're talking about neo-banks (Revolut, Monzo, Starling, etc.) or the high-street banks (Barclays, HSBC, Lloyds, etc.).
Some of the neo-banks (less so, Revolut) would be a rounding error in Apple's market cap valuation. Relatively "cheap" for Apple, more feature rich than American alternatives, and for good measure wouldn't bring with them the legacy issues you mentioned that are associated with the dinosaur institutions.
