Aha, thanks mckha489, that's great. I'm working with both FindMyPast and Ancestry but hadn't got to FamilySearch yet.
I've found records so far, but as the names aren't particularly distinctive (and I really don't know NZ geography), I'm finding it difficult to confirm if they are the correct one.
However, one of the names is Kipps Baldwin, so I think I'll pin him down first, see where he gets to and look it up on a map, and then try and patch in his siblings round him!