The Christchurch Heritage Trust has a web site.
The site is showing "under construction."
http://christchurchheritagetrust.co.nz/

A Facebook page has been set up for Shand's Emporium:
https://www.facebook.com/Shands-Emporium-1028032960563934

A Facebook page has been set up for the historic former Trinity Church:
https://www.facebook.com/Historic-Former-Trinity-Church-974806579227027/timeline/