I think the aborigines, the worlds oldest continuous culture, immigrated from Asia - all descendants of the original Eve.
btw Capt Cook, brilliant seaman though he was, didn't "discover" it. The Dutch were there earlier and La Perouse was there at the same time as Cook - in fact neither were particularly interested in the land but Cook had been instructed to claim the land, even though Britain didn't have any use for it.
Then as fortune would have it the American War of Independance occurred, Britain had a mad king on the throne and the folly of losing America ensued (ref Barbara Tuchman - The March of Folly), so in 1788 the First fleet set out - and the rest is Australian History.
Now increasing Australia's "older and betters" are of Chinese, Indian, Middle Eastern, European, and even American background.
They have little use for England, except for nostalgia - Enid Blyton and that sort of thing.