The EU-Australia trade is currently done under the 2008 EU-Australian Partnership Framework, this is not a WTO arrangement.
This was the first step which later led to the 2018 free trade agreement talks between the parts, and this first step is essential for the free trade negotiations because it levels the playing field. You have heard that expression before, haven't you?
Then you also know why Britain can never get a deal with EU as long as they are not willing to conform to European standards, standards that both Canada and Australia thought was good for trade.
A no-deal exit from EU means WTO trade rules and not an Australia deal!!
Edit:
link to the 2008 EU-Australian Partnership Framework
https://eeas.europa.eu/sites/eeas/fi...k2009eu_en.pdf