I really wish the Brits would have a dedicated practice frequency. The volume is practically turned off all the way across England. England is by far the worst area in the world for un-necessary noise on guard.
I'd agree about the practice frequency but 123.45 is allocated elsewhere, as per the CAA memo (FODCOM) issued some time ago.
However, I'm repeating myself but speaking as a UK based ATPL holder, the majority of "incorrect" calls I hear on 121.5 in lower airspace come from airline pilots who incompetently select the incorrect frequency and seem to think they are speaking to a handling agency. I heard three such calls in a one hour trip over central UK earlier this week - so whatever happened to the basic principles of proper r/t use? It's certainly more common to hear this type of inadvertent call these days, rather than (fully legal, authorised and correct) "practice pan" calls that some airline pilots themselves get so upset about.
Is there something difficult about modern airliner radio boxes which makes incorrect selections more likely, or is it a training issue?