The Free and Independent Republic of Australia

[9 Fanged Hummingbird]

As per title, with what sort of PoD's can you reasonably use to get an independent Australian republic sometime in the 1800's? I'm not gonna be too strict here, but bonus points if you can somehow involve the Eureka rebellion and/or Ned Kelly for extra Aussieness. And what would be the likely consequences of this occurring (please don't get too caught up in the how like all my other threads end up)? One of my ideas ran somewhere along the lines of having even more migrants to Australia, including convicts, Irish, Americans, whatever, to have that many more possible dissidents and more diggers. So perhaps a consequence would be a stronger Eureka movement, that either fends off British attack and inspires a wave of "Australian" nationalism (never mind that most of the diggers are foreign) or is more brutally put down, inspiring a wave of Australian nationalism that likewise spreads across the continent. As a result, there are more and more uprisings that evolve into outright rebel movements pushing for freedom from the British Empire. And somehow they succeed and manage to unite all the Australian colonies. Is this plausible at all? If not, what would work better and how would things reasonably end up?