But it goes all the way back to common law. Basically the bank is a customers agent and must obey instructions to the best of its ability. It must exercise reasonable skill etc obeying those instructions. But unless it suspects fraud it cannot disobey. To quote: a bank is not required to act as an amateur detective.
There is very little room for them to decline a customer instruction once given. It needs to be pretty blatant fraud or otherwise illegal. Sending money to another account is neither on the face of it.
