Here's the web links to both and only shops in Chch:
kitesurf.co.nz/kitesports.co.nz/Here's the kiting locations minus the Estuary
I was just there and I also took my kite gear which just turned out to be excess baggage because the conditions were sh1t.
I also had to buy a better wetsuit yep you need a wetsuit there all year round if you live in Aussie you won't handle the 14C water temp which the the temp NOW !
Bloody cold miserable and I didn't rate it at all.
I got out 3 in 3 weeks in crap cold conditions.
There is a good surf break though about 30 mins out of the city at a place called Waikuku Beach
www.surf-forecast.com/breaks/WaikukuBeach.shtml that has some decent size wave riding I went there mostly for the waves, feet felt like ice blocks after about an hour kiting.
Coming from Perth I can tell you I didn't enjoy it at all due to the weather conditions.
The locals are used to it and they are pretty hardened to the cold it seemed but man I wasn't and couldn't do much more than an hour in the water at a time.
3mm wettie minumin.
Let me just say I was glad to arrive home in Perth for a kite.
I'm sure they have there good days but I never struck any.
The wind didn't blow much when it did it seemed to be mildly stormy conditions.
I suppose if you lived there you'd put up and aclimatize to the conditions but it makes you feel blessed living here thats for sure.