Jack, saw this today on Aussie eBay. I have no connection with the seller, nor knowledge as to it's worth or not, but it looks interesting...
http://www.ebay.co.uk/itm/WW1-Austra...EAAOSw-K9ZGh2r
Pukman, you may find something if you look around the Australian archives site, linked above. Some (but not all) records are online now.
Cheers, Tim
Cheers, Tim