These services operated for quite a while,something like 1975-84,with a mixture of VC10/707/747.I doubt if many in this country knew they existed.
In 1983 it was a 747 JNB/SEZ/CMB/HKG/OSA/NRT/ANC/LHR.
I flew on the HKG/LHR portion that year and remember a very long flight.We sat in ANC for 3 hours as a favourable wind would have put us in LHR in the middle of the night.