Sid Said:
I hope you will read the AIP before parking there, as the triangle you are referring to is a helicopter aiming point located on a taxiway area
No-one mentioned parking on the triangle at LHR because no-one can, but although it's known as the "HAP" it is surprisingly the only helipad at that airfield. I land there probably more often than most (now at about £4500 a pop, not many folk bother). Arriving helicopters are held off to the south of the airfield by ATC until the taxiways are clear. After landing, helicopters are directed to taxi away behind the "follow me" vehicle. We normally
park on the Royal suite, although sometimes other stands are used. Departing VFR helicopters are required to taxi back to the HAP, which is much better than having to join the queue for the main runway, as we always had to do by night some years ago.