Dave
Let me know if you find them in Aus otherwise perhaps we could split postage between a few of us?
I know a couple fellas in Brisbane that want one including me.
I would suggest plotting all postage local and international
$3.75 Aus post + 16.50 is still cheaper for 2 units
$4.33 Aus + 11 international cheaper again for 3 units
$4.90 + 8.75 for 4 units etc etc
$18 Cost of valve obviously on top of postage