Just had another flick through the Jersey registration. One of the benefits of ownership is that you are outside the EU and UK so can temporarily import your yacht into the EU for 18 months without paying VAT or duty. Jersey say this is only available to non-EU citizens, but other official sources say non-EU residents and others just the flag must be non-EU. You'd have to get advice on that, knowing that you want to import in your wife's name to NZ eventually.
Gibraltar is very similar regime too I think.