Roughly a third of convicts sent to Australia were Irish, a good number political (Fennians), in the 1891 census the Irish made up about 27 percent of the immigrants from the British Isles. Scotland accounted for roughly 12 percent.

Together the Scots-Irish block in pre 1900 Australia was comparable to that in colonial America circa Indpendance - some US States had a greater weighting than others.

The two countries were intertwined: https://en.wikipedia.org/wiki/Catalpa_rescue