Royal Brunei has some very good flight prices - full service airline for under a grand to London return.
FlightScout has an index of the best dates to search: http://flightscout.co/au/cheap-flights/melbourne-australia-t…
And if that doesn't suit, the same link has some Air China flights for only a little more.
Example dates: 26 Nov to 1 Dec, 10 Nov to 15 Nov, 2 Nov to 7 Nov.
These dates are after Royal Brunei are removing their Dubai refuelling stop, saves 3+ hours