You may want to wait a couple of months before trying to book this for next year.
Yeah, usually max 10 months in advance, 9 for some carriers.
This getting me nowhere is it ?
Hey, you've got several pieces of superb advice there!
As a regular Perth visitor who has many friends and colleagues in Perth who travel a lot, I can tell you that the strategy above - get Air Asia X or something cheap to a SE Asian hub - is exactly what they and I do when looking for a long-haul J class fare.
Also, your original post was not very clear - it could be taken to mean you want a fare starting in Denpasar, I interpret it as you starting from PER.