So I got sick of waiting for Windows 10 to download, I saw it had appeared in a hidden folder, but was waiting on Microsoft to flip the switch for New Zealand. A bit of googling revealed that you could download the installer from Microsoft’s site (if you already had your computer approved). The trick is that you have to make sure your locale/region/language etc is set to English (US).
Once that was done, the install went well. We can’t use Cortana in New Zealand, which sucks, but then I have gone off Windows over the years, I’m happy with my Mac. My PC is for gaming, so the next step is to test all those games out! If only I had time… :/