the way he handled the backtrack instruction would have sent red warning lights flashing before my eyes.
Without rereading the transcript, I understood that there was a changeover of controllers between the point of departure and point of approach. The instructor did say when booking out that this was the lad's second solo but it is not clear whether that information was passed on.
A call-sign of "tyro" would plug that particular hole in the cheese.
Cheers
Whirls