Chas-
I'm sorry to hear that you may already be showing evidence of castration resistance. I think abiraterone is a good move, especially considering its excellent results this week for non-metastatic castration resistant PC.
If you can't get the genetic testing done inexpensively in OZ, you might want to consider a very inexpensive version called Color Genomics, which only costs $249US. i don't see why you wouldn't be able to send it next day from Australia to the US. Perhaps email them at orders@genomedx.com and ask if they will ship a kit to OZ and what the charge would be. Here's some info about
it:
/pcnrv.blogspot.com/2018/02/inexpensive-screening-for-germline.html