However be prepared to get binned off the freq sharpish if an emergency calls while you are doing your PP.
I'm reminded of the old Vietnam war era yarn (a true one) of the F100 driver (that's a Super Sabre, not a Fokker, for you young 'uns) who made what can only be caled a classic calll on 243.00, (which was commonly known then as "(US) Army Primary").
Two US Army helo pilots were (as was all too usual) babbling on on Guard when the F100 driver called up and said "When you two gentlemen are quite finished, I'd like to squeeze my Mayday in." ... and proceeded to give his (very cooool) Mayday call.
At the risk of incurring the wrath of what seems to be the majority of posters here, I'm afraid I'm with the naysayers. 121.5 is an emergency frequency and in every other country in the world, isn't used as a practice frequency. No one in his right mind would object to having his peacful Sunday afternoon interrupted by a genuine call for assistance, but even after reading all the posts in their defence, these "practice pan, practice pan" calls quite honestly amaze me.
If this wonderful service you have in the UK is so vital to trainees, why in the world don't you have a dedicated frequency for practice calls, (as the military has with UHF)? All the comments about the necessity of giving a student confidence in using the system don't wash with me. If you take that argument to its logical conclusion, a student would be required to
actually experience every emergency in the book right through to its conclusion.
Off to my trunk now to see if I've still got my old tin hat. I fear I'm going to need it.