Bob I accept it is not ideal and as a great believer in standardisation I feel I may be taking a bit of a hypocritical stance, especially talking about early training.
However my feeling is that while we can get pedantic over some things I think the business of airmanship is getting lost in trivia a lot of the time,perhaps the guy landing on the wrong runway is such an example.As a practical operator I stand by my view, in fact I can't recall the last time I made the call in question as I am not current in light aircraft.
What I do know is that the guys you are teaching who go on to fly for the airlines or military will end up operating in places where the niceties of UK RT will be a luxury they rarely enjoy.
For the other gentleman it is nice to know somebody is on a LEFT downwind after making his 'downwind' call- but you still don't know where to look for him unless you are assuming the runway he's using.I accept it is often obvious but what about the times it's not?