Wasn't Heathrow built on what was originally Heston airfield, which was Fairey's 'home base'??
Heston's about three miles away to the North-East. The BA Speedbird Club has (had?) its facilities there, playing fields on the old airfield grass.
I\'ve been going through the Skyliners book of pix taken at LHR in 1962. There\'s no Fairey hangar in sight, but a very large black one on the South Side with HUNTING-CLAN written across it in big white letters, except the -CLAN is very faint.
Is this the one you were thinking of?