Kelvindale seems to suffer from a rather arbitrary council rule that you can’t have grit bins closer than 200m to one another. Given the number of steep hills and tight corners in Kelvindale this makes for some pretty dangerous conditions (Weymouth Drive, Winton Drive, Balcarres Avenue). The ‘Find your nearest Grit Bin’ service on the council website isn’t working either, so if the roads and/or pavements are treacherous around you, please report it to the council on 0800 37 36 35. Here’s the winter maintenance page of the City Council website.
Pestering them might be the only way.