Just expanding on this deal https://www.ozbargain.com.au/node/769659
Snacks/meals/beverages included
Base fare has no checked luggage
20kg is an extra $20 each way when booked direct with Malaysia Airlines (also 10% child discount and 1 free change)
35kg an extra $140 each way (also free seat selection)
Flights available from 4 Australian airports to London Heathrow.
Flights available most days in October to November, can depart last few days of September, return first few days of December in some cases. No need to post examples because there's so many dates available right now.
Skyscanner provides links to book on multiple websites, booking direct with Malaysia Airlines is slightly more expensive.
Layover is pretty good, longest I've seen in the ~5 flights I've looked at is 7 hours, most seem to be 1-4 hours.
Also, in the link to the deal, changing the URL from "lond" to the airport code of your preferred destination may reveal some good deals. Alternatively, put in any fake airport code (e.g. fxb) and it'll show the cost for the cheapest flight from Australia to every country (found by people on skyscanner) - actually finding the specific dates may be a bit harder.
Too soon.