Perhaps they are just refreshing the web page with updated stock.
I checked the links and the Canadian, US and UK had a large selection of refurbished Macs while the Australian had nothing.
I'm sure it will reappear soon enough on the Australian website.
Mac Mini i7 (mid-2011)
Arguably, if it exists in reality, it is realistic
If proof requires certainty, then arguably nothing can ever be proven
David Suzuki Foundation