Crabthing,
If you want to know, (and I suggest for the sake of your general well-being that you find out soon), just how much ATC at LHR bend over backwards to help out Heli's in the LHR CTR then speak to any of the Pilots from the Met's ASU or Virgin HEMS whose daily grind involves going just about everywhere within the CTR that ATC wish they wouldn't. As has already been stated, their task is to keep the lumps of tin away from each other and not to make up for a lack of planning, forethought or poor time keeping on the part of the pilot.