Was a Penal Colony and small settlements the only action taken? or was there any large colony or even nation building efforts done to claim and populate such an enormous amount of land?
I feel you may have underestimated the level of their "reaction". Australia was first discovered and named New Holland by the Dutch in 1606. The first serious British explorer (Cook) didn't sail there until 1770, and the first British settlement wasn't initiated until 1788.