One needs a thorough ground briefing, with "to do" points written down, and understood, and only then should one go flying.
Agreed. However, the UK ppl does include some basic handling on instruments, so it may well be a good idea to do an "assesment" flight so that a) the instructor can see what the student can already cope with, based on his/her previous training as part of the ppl, and B) so the student can get some idea of the mental effort required on their part. And as it is a legitimate exercise I don't see why it can't be logged.
I think flight simulators are a great idea, but nothing beats actually being in real weather.
Next flight I would expect a full briefing and debriefing, however.