It all depends on when and where you are going. The majority of AEU flights from LGW are on the 757, each seat having 36 inches of legroom, so at 6ft4, you should'nt have a problem. Alternatively, you may get a flight on one of the 737-300s, where the legroom is the standard charter config. Rows 1 ABC and 14A and 14F all have bags of legroom. Where are you going and when?
Regards
Mike