Arrival in New Zealand
One of the abiding stories about Garrett (and there quite a few) is that he arrived in New Zealand "about 1838". Evidence to support that contention is, however, in short supply.
Everyone says he was working for the Weller Bothers from 1838, but no-one produces documentary proof of that. I suspect it is one of those things he told everyone and it has simply been repeated unquestioned.
However, the Hocken Library has a number of documents relating to the Weller Brothers. One such document is the hand-written Journal of Octavius Harwood. It contains an entry for January 18, 1841, which refers to [Garret Hopper] Clearwater. This is the earliest reference yet cited for the presence of Garrett at the settlement before the immigrants arrived in 1848. It also supports the 1838 contention.