This ticket is part of a multi city ticket, SYD>CNS, CNS>AYQ, MEL>SYD. I phoned about upgrading and they said I could upgrade the SYD>CNS flight at a cost of 1491 AUD...per person!

"Dan1113 +1" as mentioned above, haha, is very stressed at the thought of the SYD>CNS flight in particular in economy, as it is 3 hours long, so I am trying to figure out how to solve this. They said the upgrade in cash is possible but it changes the whole ticket (with 2 other legs) to economy flexible and prices them at the top price available now rather than any price online.

They said it would be their current phone prices if I cancel and rebook with the credit, so the price would still be 1491 AUD, and if I just don't turn up (having booked in business in a separate, new booking), since it is the first flight of this multi-city ticket, the other 2 flights would be cancelled, which is obviously not ideal.

The SYD>CNS flight is not available with avios in business either, so that's of no use. (Ironically, the MEL>SYD is easy to find with avios and it being my last leg, that's an easy one if I want to book wth avios and just skip this last leg I suppose...but it is this first one that I am more concerned about!)

Any thoughts at all on how to get out of this pickle?