Unfortunately your first option won't work either because the 241 has to originate from the UK.
Have you tried looking to buy a J ticket? ISTR figures of under £2k being mentioned with some of the ME carriers.
Will check it out.
I forgot about that , so option 1 is off the table.
I think LHR-HK first and then HK-syd return on a paid ticket might be best.
Many thanks for the comment re origination. Saved me a real problem as i was looking at booking some legs.