Just looking back through some of my old 70's LGW photo's, how about:
Southern Cross (anyone remember their 707?)
Saber Air (Singapore)
Donaldson
Wardair
Modern Air Transport
ONA
Pomair (Belgian DC-8/DC-6)
APSA (of Peru, DC-8 that operated for Iberia/Aviaco)
Interswede (DC-8)
Spear Air (DC-8)
Airlift International
Great days...!