These are available on Ebay and a few dealer sites,there were a large amount of these found in an factory in Melbourne I believe and as stated these were produced at the end of the war to be worn on the coming home tunics that's why you are seeing them all over the place.
http://www.ebay.com.au/itm/WW-1-25th...MAAOSwa~BYbEbb
I have shown an example of what is out there BTW David is a trusted dealer.