Cheap return flights to London with Etihad. $799 from STA Travel, for travel between 1 Feb and 31 Mar 2020. Book by 1 Oct 2019. Similar to these deals but cheaper.
Departing airport: Adelaide (ADL) or Melbourne (MEL).
Update: See this comment from muncan. Apparently this offer is for Students & Teachers only. $929 otherwise for Adelaide to London.
So when u leaving?