Asking where the the run up point is.
There are very few airfields in the UK where the "run up point" is depicted on the airfield plate (I'm talking ICAO and Jepp/Botlang). And to be honest, I don't see any harm in asking. As the old saying goes, if in doubt....
As for the others, who knows?
The biggest problem I hear at the moment, is pilots not reading back the type of service that they are receiving i.e. RIS, RAS or FIS
For example:
ATC: G-CD Runway 23 in use, left hand circuit, QFE 1002, flight information service report field in sight.
Aircraft: Runway 23 left hand 1002 and wilco G-CD
ATC: G-CD that's a FIS
Aircraft: Roger, G-CD
At this point ATC normally give up.