I believe we answered this via email, but for others reading this”
If you are using the plug-in version , make sure you have the Australia map set on the site where you have the plug-in installed. As far as the search by zip code, that is entirely dependent on what Google determines. You will need to reach out to them. You might be able to add the append to search short code if all the locations are in Australia on your customers site. That would require the Experience add-on to use that short code
I have tested the zip code 2000 on my test site page for Australia and no problems returning that zip code. ( See attached, we are also using the append to search Australia short code)
if you were using our SLP SaaS we could add some addresses into our list for the search engine to return the correct zip code response before it uses the Google API..