My current flight school seems to think I need to pay for dual hours even when I am solo, as I am a student. This seems a lot like typical aviation school bull to me, but is this something to do with what the CAA has stipulated and is just the way things are done?
This was standard when I was doing my PPL. The justification is that you are flying on the instructor's license.
The instructors loved it. On a busy day (not many of those) they could have several solo students doing x/c flights, and they were getting their hourly rate paid several times over, while sitting in the cafe.