Sean, afraid your skills from what you listed wouldn't be of any use as registering as an Electrician in NZ, sorry bud.
From what i can see you have just two city and guilds, PAT testing and the UK regs, Part P is not a qualification, its a building standard (even here its not a qualification). So i am assuming you have no formal electrical qualifications such as apprenticeship or 236 / 2380 or its newer equivilant? Because the Part P knowledge and the UK regs are obviously no use in a different country with different regs, so thats leave you with just the PAT certificate, and all that will give you in NZ is a foot in the door maybe as a appliance tester in NZ, but then you'd still need the NZ regs exam first.
You will need a 4yr apprenticeship AND an NVQ as an Electrician to become registered in NZ as an electrician and even then there are still two NZ exams you would have to sit before being allowed to register there. With your PAT certificate you maybe able to get in NZ and sit the two NZ exams, and work as a appliance tester but only after the two NZ exams been sat and passed first and only as a guy testing kettles and the like.
Sorry i don't bring good news Sean, but no point lying, with the qualifications you list, the NZ board (EWRB) wouldn't be of any use to you right now, and from am EOI point of view, your city and guilds wont get you any points at all.
All the requirements are here:
http://www.ewrb.govt.nz/content/overseas.html
Myself i had a mission with becoming registered and only managed it after being in NZ for 6mths and sitting there exams etc first (and i have a UK 5yr electrical apprenticeship and HND in electrical engineering!) so i have a good idea whats involved in getting NZ electrical registration.
I would suggest you either if you can claim points for your wifes career? Or just wing it and get to NZ and find some work and take it from there..Sorry.