Genghis:
That's possible, but most controllers I know tend to use 'orbit left/right at the end of the downwind leg and report (ILS traffic) in sight' rather than 'extend downwind' etc. RAF pilots as said before, will tend to maintain circuit height and go round on the dead side to reposition downwind. Could it be due to FISO's who of course, cannot actually instruct the pilots to orbit? Second thoughts no, because you don't get FISO's and ILS at the same airfield (unless of course, you know different!)