It’s working for me in the UK, not too helpful I know but think AUS should be covered according to Sonos.  Have you tried adding on the the PC Application?

Check the country is correctly populated for your account at Sonos.com

Thanks, that was it, now appears in the list, however my new issue is that I can’t add it. I select it, authorise with Amazon username and password, get a success prompt from Amazon, however go back to the Sonos app and just get a spinning wheel and eventually a “something went wrong”. I’ve tried a few times.

If you have the Amazon shopping app on your device, you could try removing that and adding Amazon Music again. If that doesn’t work, then you’ll likely have to contact Sonos Support.

I tried on an iPhone, iPad and Samsung S22, all devices had issues trying to add the music service. I eventually downloaded the Windows Desktop app, and that worked! Could add Amazon music along with a local radio station that was also failing when trying to add.

The ecosystem seems to be very much a “work in progress” in some respects :)

It’s a little ironic the “easier, faster and better” app can’t even add a music service!