Alrighty, a complex deal for you today, but if done right, you're looking at an amazing holiday down under, departing from anywhere in the UK, with stops to some of the best destinations in SE Asia along the way. These work both as 2-in-1 trips (UK -> SE Asia -> OZ/NZ -> UK) or you can add an additional stop on the return leg to make
it a 3-in-1 trip for the same price :-)
These are multi-stop trips, so you have to make sure to enter this correctly into Google Flights and Momondo - you can use our example itinerary below as a starting point and then change the dates, destination, and stops as needed to fit your plans. Sadly, there is no easy calendar tool to find the best options, but the example dates listed below seem to work for nearly all routes.
Note: for London departures, the prices in Momondo will often be lower when departing from one airport and returning into another (such as out of Stansted, returning into Heathrow).