Michelle,
I have not seen the plumbing in Australia. My wife who lived there a few years has suggested to me that the piping may be different than what I am used to in the US.

I leave you with this quick note, you can decide if it applies in your case.
If a threaded pipe or valve is too tight to remove, I sometimes heat the fitting, which then expands, allowing easier removal.
Regards,
Terry

• Love Plumbing & Remodel