But you haven't confirmed bank details - it's quite possible that a different branch of the same bank in the same area - or even of a different bank - will have a very similar sort code.
And you haven't verified the account number which is just as important and easier to get wrong. (8 numbers, no gaps - at least the sort code is three separated dinomes).
Far safer to send a cheque in these circumstances.
If you get a transfer wrong it may be a hell of a fight. The wrong recipient may well take the view 'it's their (or more likely 'there') mistake, I can keep it'. Legally he's wrong, but it may prove next to impossible to find out who he is and retrieve the money