The BA timetable from 1 January 1974 - so the first one - has a special advert in it "Fastest from Johannesburg to London. BOAC's one-stop 747. Tuesday, Friday, Saturday, Sunday." The route was obviously a fairly early upgrade to the 747.
One page missing from the booklet which unfortunately happens to be the southbound LON-JNB services. But the northbounds were:
Monday BA022 JNB 1845 - 2330 NBO 0030 - 0620 ZRH 0710 - 0750 LHR
Tuesday BA024 JNB 1845 - 2330 NBO 0030 - 0610 LHR
Wednesday BA026 JNB 1845 - 2330 NBO 0030 - 0645 FRA 0745 - 0815 LHR
Thursday BA028 JNB 1845 - 2330 NBO 0030 - 0620 ZRH 0710 - 0750 LHR
Friday BA030 JNB 1845 - 2330 NBO 0030 - 0610 LHR
Saturday BA032 JNB 1845 - 2330 NBO 0030 - 0610 LHR
Sunday BA034 JNB 1845 - 2330 NBO 0030 - 0610 LHR
VC10s were on
Tue SEZ-DAR-NBO-NIC-LHR
Thu SEZ-NBO-EBB-LHR
Fri BLZ-NBO-NIC-LHR
Sat LUN-NBO-KRT-LHR
Sat MRU-SEZ-NBO-CAI-LHR
Sun SEZ-ADD-NIC-LHR daytime
And the VC10s also did:
Wed BA045 LHR-EBB-NBO-SEZ, then aircraft operated BA910A SEZ-CMB-HKG-NRT to arrive on Friday afternoon
Thu NRT-HKG-CMB-SEZ BA911, then the BA048 SEZ-NBO-EBB-LHR
Sat BA051 LHR-NBO-SEZ
Sat NRT-HKG-CMB-SEZ-JNB
Sun BA910B JNB-SEZ-CMB-HKG-NRT
BA were indeed running VC10s on some of the Australia services at the time - Sunday's BA745 left Brisbane at 1530 via Darwin, SIngapore, Calcutta, Doha, Damascus and arrived in London at 1020 on Monday.