SAS,
I guess, in the same way that you have experience in judging whether a PPL could be construed as a danger to themselves & others (& so presumably sectionable under the mental health act

) we lowly PPL's have had ample experience in assessing whether an instructor is performing satisfactorily during the training flight.
Personally I am used to being asked what specifically I would like to cover during my reval training flight (I tend to practice the emergency procedures as much as possible anyway so this is never a bone of contention) rather than being told (briefed) on what the flight will cover.
I would be particularly put out if I had to waste 15 mins flying time to demonstrate a PFL that I had been practicing for an hour the previous week (I have to say I would demonstrate the exercise but I wouldn't be happy about it, mainly because I could be spending the time constructively learning & revising other aspects of flying that would be of far more benefit).
Ultimately we will disagree on this subject ad infinitum

so we will just have to agree to reserve our respective defences (refusal to sign off V civil recovery action)
Still, it's been a stimulating, if somewhat pedantic debate so thank you

.
Regards, enq.