It will take some digging. I would rule out a death in California first before returning to research a path back to Australia.
I found this in Ireland in an Imperial World.
http://ndl.ethernet.edu.et/bitstream/123456789/12958/1/217.pdf
... John Manning, the editor of the nationalist newspaper the New Zealand Celt, were indicted for ‘seditious libel’ Following release from prison, Manning left for California and Larkin ‘slipped quietly into obscurity’.19
Their source for Manning is this: Fraser, Castles of gold, 145. For more on these events, see Davis, Irish Issues in New Zealand Politics, 11–24.
Some of the wording on the profile should probably be changed. Like the research note that said he died in 1868, which is not known and is unlikely.