But then again JNB-SYD-HKG on QF would work - taking a bit more time but earning more miles/points

You don't say which FF program has your membership (BA implied). Nor whether the xONEx will be L or D. I ask since CX has JNB-HKG flights and would require one less continent (ie no SWPacific) as DPS is part of Asia. Would CX L class credit to BA?

Happy wandering

Fred