The other options:

1) Using VS you can use the Australia-Europe routing (but you need to use the First column for booking in "Upper" or VS business class), but still at 2350, it is less than 1700+1215 for separate flights.
2) 1550 + 1120 for Europe-Africa-Australia, using SA to get JNB-PER, but obviously you still have to get PER-SYD.

Not sure what VS or SA availability is like.