Hi and Welcome
Nice to see another Aussie around here.

I was looking at the Katadyn desalinator too, but I never got as far as getting one.
On eBay there was a guy in Hawaii a few months back selling them for between $400 and $500 AUD plus shipping.
I cant remember his username, but I am 90% sure he was in Hawaii.

I just settled on the Katadyn Pocket and Mini, and didnt worry about desalination. I cant justify the cost or the ongoing upkeep of the unit.

Good luck.