Not sure about Melbourne but I tried a few years back here in Perth to find a shop that could fabricate a portable pier with no success. I did talk to the guy who runs Pegasus piers and at the time he seemed willing to make a special order for one. Not sure if Pegasus is till going but one option.....
https://www.facebook.com/pegasuspiers/
It's a shame there's not many commercial options for portable piers although there's quite a few hybrid tripod piers from ATS, Ioptron, Altair....expensive though. Former company Mountain instruments used to sell a very nice pier, there's one on Astromart at the moment.....
https://astromart.com/classifieds/as...ents-mi-8-pier
There's the Astro Physics piers and Takahashi make their own. Unfortunately with the Tak piers they don't have a intermediate size, very heavy, built to order {lengthy wait} and pricey.
The Takahashi NJP/EM-400 metal tripod is worth considering, very solid, samples come up on Astromart every so often.