B747-200 were operating to London via Perth,Bombay from at least 1976.
Correct. These services were QF7 outbound and QF8 inbound. all originated/terminated in Sydney and operated via Melbourne.
Seem to remember QF doing a MAN-LHR leg as well on the way to SYD/MEL. Anyone remember where the stop-offs were?
Also correct. I'm not sure of the Manchester frequency but by that time I'm fairly sure that the routing would have been Melbourne/Sydney/Singapore/Bahrain/London/Manchester and vice versa.