Used to look after lots of company aircraft at Glos Air in the 1970s and 80s.
United Biscuits - King Air 200
Ranco Europe - Commander 690C
Distillers Co. - King Air 100 then Jetstream 200 then Jetstream 31
Guiness - Jetstream 200
Laura Ashley - King Air C90, B200, Citation I and Falcon 100
BA for Lord King - King Air 200 then 300
Westland Helicopters - HS125
JSAX corp. - HS125
TVS television co. - BN2T Islander, Commander 690B
AAH - Commander 690B and 695
That's a few that come to mind, there were lots more.
British Aircraft Corp. had a Heron and HS125 in the early 1970s.