the most popular destination in SE Asia,
That is a big call. I guess you meant "...in SE Asia for West Australians"?
The most-visited destinations by Australians in 2015 (based on ABS data to October)
New Zealand
Indonesia (my edit: I guess Bali?)
USA
UK
Thailand
China
Singapore
Fiji
Japan
India
Not much of a shock if people decide to fly two hours North to Thailand which is number five on the list but the second most popular in SE Asia.
https://auspost.com.au/travel-essent...ralians-travel
3401.0 - Overseas Arrivals and Departures, Australia, Dec 2016