Practice Pan calls aren't so much a GA (by which I think you mean light aircraft) or school policy, rather they are encouraged by the CAA. See CAP413, chapter 8, 1.3, 1.9, & 1.10, I would copy & paste some of the text, but that doesn't seem to be working.
So you might well not agree with it, but you should understand it.
GA Button,
I haven't seen anything from the CAA about not doing them while R112's in effect, although I can see while they might. Do you have a reference for that, or is it just a word of mouth request south of Manchester?