You don't indicate where you are based. I will assume eastern Australia.

Even so the strategy I use exPER will sort of work. Fly economy to SIN or HKG and purchase (online or TA) a second ticket in Y+/Business from there to Europe. BA seating/service is perhaps not quite as good as QF, but it still is better than QF Y and Y+ will provide full cross-crediting. And BA sometimes offers "cheaper" upgrades during the "manage my booking/online check-in" process.

Also AY provides a quite reasonable J cabin fare exSIN/BKK/HKG

And of you used a one way ticket to get from Oz to SIN/HKG/BKK you might be pleasantly surprised on the cost of a round trip ticket to return (and go back again)

Happy wandering.

Fred