I would have thought this would have been easy but many of the links did not work and the resolution of the available coverage map was not adequate to pinpoint the location for an aerial alignment.

The actual physical address appears to be 192 Browns Bay Road.

http://www.northshorecity.govt.nz/YourCouncil/PublicDocuments/DistrictPlan/Documents/current-modifications/pine-hill-NOR-summary.pdf

An exact location can be found by using the North Shore City GIS Viewer and looking at the Satellite image found here after clicking "Start GIS Viewer". The antenna is clearly visible besides the water reservoir, although it may have physically changed as the image was taken in 2008.

http://www.northshorecity.govt.nz/Services/PropertyInformation/GISViewer/Pages/default.aspx

I hope this helps others on the North Shore with their DIY UHF aerial installation.