Can we get rid of this myth
'The bank reimbursed funds to defrauded customers'
The £2.5 million was stolen from Tesco Bank, no customer money was stolen at any point, 'the bank corrected the numbers in some accounts' is what they actually did.
When you deposit money in a bank it is an unsecured loan from you to the bank, the bank is free to do anything it wants with that money (including lending it to someone else). Normally you have the ability to call in this loan on demand however if the bank broke then you have to claim off the insurance (bank guarantee) or get in line behind the guy who waters the HO plants.
If I lend you £20 and at sometime later someone steals £5 from you that theft is from you not me, you still owe me £20.