I spotted these today in a shop down the freeway west of Sydney (I can PM any interested member the details if they want). There's 2 in the tank, they look like a pair but they weren't advertised as such.

They're about the size of a bread plate, super clean and carrying great condition. You've got to see these things in person!!

If only my tank was complete. I had to leave before I did something stupid, like buy them with no where to keep them.