The only flights that Qantas operates out of London are to Australia and Singapore.

Qantas is not an incrredible airline - it is an average airline ; there are other much better airlines to try out. If travelling in premium cabins, perhaps give Etihad, Qatar and Oman Air a try first

If it was a BA flight ( or any other airline ) the situation would have not likely been much different. There is zero chance that BA would have told the passengers to rebook themselves