You might wish to try for a lower price here also:
http://www.bhphotovideo.com/c/produc...o_Focuser.html
or here
http://agenaastro.com/meade-1209-mic...ser-07080.html
$423 US is pretty steep and trying to capitalise on sales. I believe either of the above send to Australia, but postage may not be cheap. I may have one in box, but not sure if I wish to part with it.
Kind Regards,
Matt