Welcome to the NZ board.
May I suggest that you try looking up the CENOTAPH enlistment records, that can be accessed through the Auckland War Memorial Museum, and also our PapersPast web site.
I found hits for one of the surnames you appear to be researching, in both sites.
If you have names you are prepared to share with this public forum, there are several very experienced researchers who offer assistance from their acquired knowledge, of available historic records to be found in NZ archives, across our islands.
Alan.
PS. 20-9-25 I have supplied by PM, links to several named individuals that may be of interest to the poster.
Traditionally UK emigrants travelled to NZ in the hope of finding better prospects. When you research into their emigration, they have often followed people, or family known to them.