NZMCA is an interesting requirement.
Currently at this time, Spark do not offer this. Spark do have an ongoing trial looking at allowing a holiday home location.
The spark setup is currently a Fixed wireless setup (be it generally without antenna as honestly that doesn't always improve things in the customer's eyes)
Spark prefer to have the network in optimal condition, which is why we do things like stopsells while we upgrade areas where the wireless service is heavily used at peak.
This allows us to ensure our customer's still get the solid experience.
Where i land on the fence, i get a fair bit of viability to this and are always impressed with our LTE rollout targeted at the network performance - Often upgrades are adding multiple carriers at once; jumping to "4.5G"
Interesting and completely understandable I would have thought spark would have been better positioned to do something like this as they own more mhz on band 28 and presumably this is what camper vans would connect to more as they are more likely to be in remoter or holiday areas.
TBH I have used sparks network almost exclusively since the days of CDMA and I am a fan I was so hyped that you got band 28 to the Waikato first I brought a new phone to use it.