HI,
So I imported my Cali from UK to NZ when I immigrated.
Stuff to be aware of -- the gas cylinders are different, you have to butcher the lid of the gas cylinder cabinet to fit a NZ cylinder. Also need a gas fitter to fit new connections and certify it - which costs.
To be able to register the vehicle you need it to have pass all these checks that it's 'built to NZ standards

' of course it is, but it is all form filling and more checks. Then costs with getting the unregistered vehicle from the importer to the company which does the checks so it can be registered. It just goes on and on and costs at each stage.
There is a cheap UK shipper who will put your van in the spare space in a 44 foot container when they skip caravans over. PM if you want the details, but the shipping is all a bit unreliable. Sometimes when the ships are running late they will skip a port, so your camper van may get unloaded on the wrong island.
It's all a bit of a pain and probably not worth the effort for just a holiday.