Perhaps selling 1 or 2 of that model, to NZ, via online shoping is just more trouble than its worth for Dell, so they really dont care
It may also be to do with lipo shipping restrictions.
Perhaps Dell are using a ridiculously expensive courier service so they dont have lipo shipping issues to deal with ?
Youre taking a chance trying to ship anything with a lipo batt in it nowdays. Some couriers simply take a hard line & just ban everything with batts, and goods just get stuck at the border .
Even youship,youshop lists lithium batts as prohibited items .
Its a grey/murky area as to when & how batts can be sent, so many couriers find it easier just ban them
I don't think it is that grey/murky if you are able and willing to jump through the right hoops. I parallel-imported a notebook via my sister who lives in the States. She had to go to a fair bit of trouble getting the battery information she needed from the manufacturer to fill in the necessary forms, but once that was done she was able to ship without further problem, also not at this end.