For what it's worth I flew LHR - BOM - PER - MEL - AKL with BA in summer 1978. It was then a relatively new service with B747-200's with RR engines that had the legs to do BOM direct from LHR and similarly BOM - PER direct. Previously BA using B747's with P&W engines had to stop in the Gulf on the way to BOM. LHR - SIN non stop was still a dream until the 747-400 came along.
From memory QF had yet to have anything with the same range apart from the 747SP which I think at that time they were only using across the Pacific.