I found an old photo in a fairly cheap old frame in a wonderful antique shop on Dominion Road today -- and it has helped solve a bit of a mystery for me.
Back in November 2008, I posted a shot I took of the Wade Hotel at Silverdale. (Despite the fact that the shot was a distance one, from across the busy street, it must have been thought of as a bit of a cracker by whoever put up an entry for the hotel on the View Auckland site, because they nabbed it from Timespanner and used it on their site. Eh. Such is the way of the 'Net. I've emailed them and asked for due credit.)
Anyway ... this photo I found today looks like the centre part of the old hotel. I found, as well, that Maurice Kelly's original Wade Hotel burned down in 1880, so this must be the rebuilt version. So, an answer to my question almost two years ago -- the centre of the hotel, still to be seen today, dates from the 1880s.