I think GH6 hangar lease runs out in the early 2030's. BA were holding onto it in the hope of prising some new facilities from BAA / GAL. Not likely at the moment. As to the previous hangars, No1 was the 1-11 hangar which became the MT base, No2 was workshops, No3 was 707 VC10 and latterly DC10, Not sure about the wooden No4 but burned down one night when I was working on the ramp! The other No4 was the Airtours hangar which carried out L1011 and 737 work. No5 was for DC10s. The only one left is No6 the old Laker hangar. OSU had a short stint in No7 after Dan Air and prior to Virgin taking over. there were also various lines of 737 and 757 major maintenance at times. Thats how I recall it since the 70's!