Originally Posted by number_6

The problem is the lack of North America-Africa flights, and 2nd entry to Europe is not allowed (except for Accra or Lagos origin, which isn't what you want). However CX has ticketed LHR-HKG-JNB-SYD and I believe this is 100% legal (haven't checked recently), so you can do this on an xONE5 eastbound routing. It isn't legal westbound or without including Australia (as you cannot exit Africa otherwise).