JP,
If you have no luck finding the Portamount or AZ5 take a look at the GSO SkyView ATZ heavy duty.
There is a review of one under the 'Equipment Reviews' section of this site, upper left.
http://www.iceinspace.com.au/44-636-0-0-1-0.html
I had one earlier in my astronomy journey, then sold it when I went to goto mounts & repurchased one recently when I realised how much I missed it as a lightweight portable mount for basic visual use. My first one came with 2 x slowmo controls, the second one with an eyepiece holder & 1 x slowmo control. I got hold of a second slowmo control from an old EQ mount & drilled it out to fit...
Andrews Communications has them for $299 brand spanking new... BINTEL also sells them for $399.
Bought mine from Andrews, think it cost me about $70 freight to Cairns, Qld.. might be cheaper for you in Canberra.
Cheers