It does beg the question "why does Heathrow need so much Class A?". We have already established on one of these threads that LAX (for example) is busier than LHR, yet you can go right up to the airport boundary at 90 deg to the runways at sub 2000' before you enter their Class B (in fact Hawthorn airport could be considered "LAX executive terminal")....Of course the IAPs and SIDs are protected to 10,000'. If you have a helicopter you can land on the roof of the international terminal, and if you want to fly in in your fixed wing, then you can (VFR or IFR).