> “The lucky 400 first houses in the trial are in the suburbs of the North Island city of Hamilton.”
...and those suburbs are...
"The initial trial aims to upgrade a neighbourhood of 400 households to fibre, in selected streets in Nawton, Grandview Heights and Western Heights in Hamilton, in mid-November."
http://www.sparknz.co.nz/news/upgradenewzealand/
...so if you live in one of those suburbs, and there's someone banging on your door next week, then you're in a "selected street".
It seems that what Spark are trying to overcome with this initiative is...
"...the process of getting [fibre] installed is often problematic and can involve lots of hassle. For many customers, that can prove a turnoff as the installation process seems just too hard."