Think it through very carefully - every country has it's issues, and NZ is no different. Whilst Brexit rears it's ugly head here, NZ deals with it's own issues - very high suicide rates amongst teens, drink driving, casual racism and many, many children living below the poverty line. It's an amazing place, but you won't be escaping polictical and social economic issues, they occur everywhere.
We lived in hawkes Bay (equidistant from Auckland and Wellington, on the East Coast) for nearly 5 years, but spent quite a bit of time in Wellington and yes, it is a beautiful, amazing place to live BUT it's not the land of milk and honey, and whilst some things may be cheaper in NZ, lots of everyday things (insurance, electricity, groceries, school fees, clothes etc) are far more expensive. That being said, we just learnt to eat seasonally, which brings your food bills down a lot, and there was far less of a ready meal culture there in supermarkets, so we ate better I think. I also made use of M & S and Next shipping to NZ, and got as much of the children's school uniform sent over to us that way - there is no real equivalent to mid priced shopping in NZ that I found, it's KMart (cheap as chips) Cotton On (more expensive but equally hit and miss quality) or Farmers (department store) and not much in between.
Housing is cheaper, and you'll get more land for your money generally speaking, but many houses are not built as you're used to here in the UK - we lived in a big, open plan house with a huge geraden and a pool, which we loved, but it had zero insulation, no double glazing and no heating other than a fire, and a heat pump, so winters (and they do have them there, despite the idea that NZ is warm all year round!) were woefully cold. Double glazing and central heating can be found, but not in older houses, and you'll pay more for it. We joke that our kiwi house was the nicest shed we've ever lived in, but it has a ring of truth to it - wooden house, tin roof, single glazed windows, gorgeous in summer, a condensation riddled health hazard in winter.
We were incredibly lucky and made some amazing friends there who helped us through patches of homesickness, helped out with our children if they were sick/I needed to work (all reciprocal by the way, I wasn't just a CF :-) ) but never underestimate just how far NZ is from the UK, and go into it with your eyes wide open. It's very easy to say 'we'll go back every year', or assume that people you love will trek over to see you, but it's a long, expensive trip to make (it cost us in the region of £6k to fly back and forth with our three children) So be very realistic about living so far from friends and loved ones. We see our kiwi friends every two years now, and that just about keeps my NZ homesickness in check.
Check out the enz forum ( www.enz.org/forum/ ) there are a lot of poeple on there, and lots of good advice. I wrote a blog about emigrating when we went, if you'd like to read it travelsofmrandmrstandthelittlets.blogspot.com/2011/09/so-mr-t-shall-we-emigrate.html