I've worked close to there but never had the pleasure of visiting. Great photo of Charlie up there Dave! Here is another effort from the TL Survey lads, Bruce has provided this photo for me of a trig in the central South Island - it has a biblical name in part.
Funnily enough my Avatar photo is taken standing on  Ref Mt Mary, Mr George and I spent a hot and unpleasant morning up there a couple of years back. Followed by a pleasant afternoon fishing in the Tekapo Pukaki canal. I haven't been up Mt Mary proper, but  is probably in the distance behind me in the photo. I'll dredge out a new pic tonight.
(I cannot take the credit for the trig build in 2007 - I was on the valley floor whilst the work was being done by one Paul Halkett. Incidentally, I don't think the "PH" in the trig name relates to Paul's efforts...)
The access notes are certainly not for this trig. If you are wondering, they relate to AAE4 G ASHBURTON RIVER BRIDGE. I'll flag the issue to LINZ.