Has anyone set up a site where Australian users can put a link to their sites?
Mine is hosted through Davis’s Weatherlink.
I tried joining the Australian Weather Network, but was told that they could not get data off the Davis hosted site.
That’s correct, nor can the regional weather network mesomaps take data from WeatherUnderground nor APRS/CWOP data from findu.com.
You’ll need to publish to your own personal weather website in order to submit conditions to join the regional network.
One of the purposes of the networks is to increase visibility of your personal website by linking from other sites, so that only makes sense if you have a personal weather website 
Best regards,
Ken