Hmm, well that lumicon off-axis guider you posted the link to us US$199 ... Say you could get that for AU$260ish then.....
Skywatcher 70x700 OTA: AU$150
100mm Scope ring set from
ADM: US$69+S/H
Total: About AU$250
Might be extra if you need some sort of attachment to put the rings on your setup.
Anyway, point is, you might be able to get a guidescope for the same or very near the same price.
I use the 70x700 for guiding. Weighs so little you'd think it's a finderscope, but surprisingly sharp optics with focus lock and good focus travel. Very suitable and cheap guide scope. I use those rings too.
Roger.
Edit: ADM: http://www.astro.premcom.com/ADM/