Don't forget the import taxes, which seem to be very random, and there is no appeal process, and you have to pay upfront in cash. I had to take £700 quid to heathrow to collect the sails. They would not release them without the cash, and once they had taken the cash (and I saw it disappear into someones actual pocket) I had an anxious wait for the sails.
We have also imported sails/masts/etc without charge, though never without hassle. Antiodotes mast and spreader sets got separated and went to different depots, but when I collected the spreader sets someone checked out both the spreaders and the mast. Next day I went to the other depot, "We've never heard of that/you collected it yesterday".
"How could I have collected something from depot A which is at depot B?"
The approach which worked was me saying, "There cannot be many parcels which are 4m long and only about 100mm wide!".
You could just about fly to NZ for the price of the import duty. Things for personal use which have already been opened do not pay import duty. Sails can probably be checked in no problem, top sections and spreader sets too. The bottom section might be a problem but that is probably the least special bit of C-tech kit.