Do so me more research:
I have heard that with a UK ATPL theory you can go to some new zealand authorized flight school to get your CPL licence (NZ price is much lower than in the UK), then come back to UK to validate it and get a UK CPL licence (call it a frozen ATPL if you like it).
To get an australian licence from a NZ one, that's quite easy.
For the low price of a CPL NZ licence, you may have 3 licences at the end, including a JAA one. Could be interesting in your case I think.
Sorry I don't have more details than that, and didn't experienced it myself, you will have to do your own research.
An other point: there is a possible progressive career path in australia, thanks to the important GA.