also remember QR are now flying to ADL (J-only), and QF, others also fly to MEL and BNE as well as SYD. a short intra-AUS trip would presumably not be a huge problem?

We routed down on QF10 to MEL and returned in J via TYO.

Do JAL still operate F to SYD? BA F to TYO and JAL down would be great

CX F TO HKG AND QF F from there a great option

QR also operate F to syd I believe?

Be creative in your routes, and note that the great circle route from SYD to LHR is effectively via ANYWHERE :-) HKG, DOH, SIN,TYO as connection points are all within 300 miles total trip distance of optimum.

I'd note I booked 2 F seats on QF 10 LHR-MEL at probably only 6 months out.

edited to add: you COULD also fly via the US but my guess is award availability transpac on QF is even worse.