I’ve used a lot of British online banking websites and phone apps. The vast majority only show the account name of the payer, not their sort code or account number. As such, most British traders are likely confirming that payments are coming from the displayed account, when actually they don’t know which account it comes from (UK Faster Payments on Bisq do not involve the account name). This means that scammers can let a genuine account age or be signed before switching to use hacked accounts which will get charged back once the crypto is released.
Another risk is a scammer using their own genuine account until the trade limit is reached and then buying 0.25 BTC and claiming their account was hacked and that they weren’t responsible for the transaction. The seller would have to prove selling the BTC or their bank will take back the funds, and it’s unlikely a bank would accept Bisq screenshots as evidence due to its anonymous nature.
A potential fix for this would be for Bisq to require account names for UK Faster Payment accounts.