Have just discovered, with help from JM, 2 John INNIS's and an Albert INNIS all living in West Queen Street, (Auckland?) all three on a jury list for 16 Feb, 1856. (Daily Southern Cross, Volume XV, Issue 1110, 16 February 1858)
This is not my John and his two sons, (since sons wouldn't be on jury duty aged 1 year and minus one year.

) but could be my John and brother and father.

Which would indicate John migrated there with his family, at least a brother and father, before 1851.
I don't think this rules out a whaling ship, especially since one John and Albert are described as "boatman", the second John is a carpenter.

Looking for more info at that address, can't think if there would have been electoral rolls then...maybe business listings, post office listing or something.

Was there a Portuguese quarter/community in Auckland then?
Thinking - thinking - looking - looking......