You've discovered one of the hurdles with ownership of low volume / private imports.
Not being an Autralian market import, I don't expect you'll find much locally.
Keep trying UK and their forums, or even NZ as I think they imported some there.
e.g. (maybe)
http://forum.fordsierraclub.co.uk/..
.....just Google it and
......eBay.uk (some currently listed, but freight will be a killer)
......try (no affiliation)
RS Shop Pty. Ltd.
http://www.rsshop.com.au/contact-us.html
583 Ebden St
Albury NSW 2640
Phone: 02 60235577
Mobile: 0447235577
Good hunting.....