British Expats - how long

It can be very fast if you have a job offer, relevent skills, recognised qualifications and all the documents required. I know of a couple that pushed it through in a-week-and-a-half, but I think they were highly exceptional and had everything in place.
So, the thumbnail process:

-Fill in your Expression of Interest (EOI) online. There is a draw every fortnight. If you have over 140 points you are automatically plucked from the pool and will be sent an Invitation to Apply (ITA). If you have between 100 and 135 points you will be in the pool and depending on New Zealand's needs you will be selected. Some get selected straightaway while others languish for months on end.

-If you do get selected you will be sent an ITA in which you have to provide the evidence to back up your claims on your EOI. You'll also need police clearances from any country in which you resided in for over a year in the past ten years. These clearances are good for six months. You'll also need medical reports including blood tests and x-rays. These have a shelf life of three months. Your educational qualifications very well may need to be assessed by New Zealand Qualifications Authority (NZQA). They are known to drag their feet at times.

-If all goes well you'll be issued a resident visa allowing you to enter New Zealand and get a resident permit where you have the right to stay indefinitely.

So, now that I've gone through the blah blah blah, you might be saying, all well and good, mate. How long does it take!?

Answer -- it depends on so may variables. If you have your ducks lined up, maybe a month or so. If not, many many months. It really is a case by case situation.

Sorry, but I'm afraid I can't give you a hard and fast answer. That's the way it is as I see it.

All the best and good luck.