Chiglet.
I was saying as it was in the book. He still got the DFC however and finished his service as a WO.
Edit: He was in fact promoted to WO on the orders of AVM Sir Ralph Cochrane, who was the AOC 5 Group at the time of the operation. It is also interesting to note that the AOC heard of Tom's action when the aircraft was still mid-channel and wanted to meet Tom when they landed - at 0230 - to hear about the whole action. They shared tea and biscuits, with a large tot of rum, in the officers mess.
It was Leonard Cheshire who recommended Tom McLean for the DFC.
It was, as you rightly say, the other way round.