Avia..please define "busy". LHR has 2 runways. It has some pretty savage noise abate protocols that ATC have to feed traffic around, particularly on the 27's. I know of no other airport where I have to call DIRECTOR with call sign only. The approach separation distances are absolute minimums and rely almost exclusively on the most prompt of runway exits. I think 'Busy" is a tadge different from traffic density, given the paucity of runways at LHR compared to the other 11.
...and BTW can someone explain again to me why LHR insist on the ATIS readback to include QNH still...and for that matter, why do they need a confirmation of a/c type??..I thought that was on the flight plan, which after all defines the weight of the aerplane and thus the levy of charges??..or am I still in the 80's???