The only time I have encountered a problem and maybe that no longer exists now that UB is gone as maybe the system was specific to them was when I sent money to the right account number and wrong sort code. I had accounts in two different UB branches so had two sort codes and I quoted the wrong account number with the non matching branch sort code. It went through to someone else's account. Turned out UB reused their account numbers across branches so if you got a sort code wrong as in a correct sort code but for the wrong branch then there was a risk it would hit a valid account combination but not necessarily yours!
There were 7 branches in the country that had that particular account number so getting the right sort code was vital! Those new checks should catch that though as name would be different.
There were 7 branches in the country that had that particular account number so getting the right sort code was vital! Those new checks should catch that though as name would be different.