Kia Ora,
I'm from Christchurch in the South Island and this city is absolutely over-run with indian restaurants. Some are brilliant and some are absolutley craphouse!! ie Taste of Bengal (anybody else from chch nz been there?). The nicesest place I've been to is called Two Fat Indians they are a resaurant and takaway. A bit more expensive but worth it if you can spare the coin

. Tandoori Palace is a well to do chain that has started in CHCH and branching onto the rest of NZ including North Island. They produce consistantly decent curries d (tho not brilliant). It is their curries I use as a yard stick with which to judge other restaurants by. To date Two Fat Indians make the tastiest curry i have ever tried. There is a chain called Shamiana which is in the eateries in shopping malls. Their carries are reasonably tasty but again not superb. I once made the mistake of orderirng a Hot vindaloo from a place called Raj Mahal. Ooohhh boy that was an experience i was almost hallucinating

. They used a lot of potato in the vindaloo and are the first resaurant I've come accross using potato in a vindaloo. Little India are also a chain. They have a masssive resaurant in the middle of the city and produce a nice curry. Another chain resaurant "Tulsi" is quite new here. I have been once, had the vindaloo. it was very tomatoey and lemony but nice. As you can see there are heaps to chose from and I have not listed all the restaurant/takeaways in CHCH. The only place you can watch the cooks (that i've seen) making the meals is at Tandoori Palace. I have watched them a few times (they move very fast!!) they always have a big pot of onion sace on the go. Once i saw a big pot of onion halves boiling on the gas ring (i assume they were making the sauce) there didn't seem to be anything else in there but carrot etc may have been on the bottom out of siight. One thing that intrigued me was the pot of red sauce next to the onion sauce pot. I have noticed there is not a lot of dicussion on this board about this or do they not have this in the UK? they use it when making the madrass and vindaloo etc.
I bought a vindaloo the other night from TD and decided that there was three main flavours: tomato, lemon and cumin + chilli i will try to replicate this in the future.