Another option is to fly to Singapore / Bangkok /Hong Kong in normal economy, and then fly WT+ from SIN/BKK/HKG to London.
Rumor has it that British Airways are wanting to withdraw from the Australian market. They may not be flying to Australia by then! Only rumours though... and the same rumours have been around for several years at different occasions. Hasn't really happened yet (although they have changed some plane types to Australia to smaller planes).
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