If he is a qualifed pilot not receiving any instruction then common sense would say P1, not PUS, not PUT. There is NO instruction taking place.
But I can almost guarantee the instructor logged it as P1 so the other pilot can't.
However, I would say it is instruction because the instructor is technically doing a refresher course and is being paid for his time. What the school is saying is the student has already got the licence but doesn’t know how to exercise the privileges properly so needs extra training before they will allow him/her to cross the channel in their aircraft.
Only in the UK!