Well, maybe @Urmasinka, having opened the other thread has some experience by now.
But searching for just “New Zealand” did result in quite a few threads concerning experiences with the FP in NZ: https://forum.fairphone.com/t/new-zealand-sim/25203/6
(Well, at least it seems the phone has worked before he encountered the battery trouble.)
(posting is from 2014, so it has to be a FP1 as well)
Well, you could try to contact any of those posters by PM, to maybe get them “alerted” and answering your questions, if they have set to be informed by e-mail.