I have had a bit to do with Garden City and can definitely recommend them out of your list of three, either in Nelson or Ch Ch.
BUT, I still say go see 'Mark Law' in Whakatane at Frontier Helicopters, you wont find a nicer guy, good place to train and he is out there working not just training! I haven't caught up with him for a while, but he used to sort out accommodation for the students, and he has a scenic op running, so maybe more chance of a job than with the others you mentioned and he knows a lot of people in the industry.
Doesn't hurt to talk to him!