Well seeing the OP is not running up against the 20 segment rule nor the 4 segments in SWP, take a day and a night to stop and visit the wine district just north of Adelaide - the Barossa or the Clare Valley.
LHR-PVG-HKG-MEL-PER-ADL-SYD-JFK-LHR
I've done the PER-SYD-JFK using the redeye from PER and even though the lounge in SYD is nice, the wait was too long. If you've got the time visit the vinyards and then get an early flight from ADL to SYD to connect.
my 0.02 $AU
Happy wandering
Fred