Can be achieved via:
BA SYD-SIN-LHR then onto elsewhere
SQ Oz - SIN - Europe
KE/OZ Oz - ICN - Europe
CX Oz - HKG - Europe
QF SYD/PER - SIN - LHR then onto elsewhere
And that doesn't cover other carriers like Lufthansa, Air France etc who go into Asia.
Unnecessary routing and too long imo if you go via EZE.
Good luck getting seats though! Can’t speak for HKG or ICN but seats are spars ex-SIN. I haven’t looked today but yesterday I could only see availability of 12 seats on ExpertFlyer SIN-LHR/LGW for the next two weeks. SQ was similarly tight to FRa, CDg and ZRH but I did see a few LH flights with 3-4 seats available.
