>>> Brexit ain’t gonna happen so why are the Aussies singing in a European song contest ?
Somebody mentions that every year!
Officially the contest isn't for European countries but for full members of the European Broadcasting Union. (A few European countries don't have broadcasters who pay for EBU membership and they are therefore excluded from competing in the Eurovision Song Contest).
An exception has been made for Australia, who hold associate membership of the EBU. If other associate members are allowed in, we could see China, Chile Mauritius and Oman (among others) competing:
https://www.ebu.ch/about/members?type=associate
Anyway, this year the competition isn't even taking place in Europe, is it?