Hi Steve,
Graze timings are very valuable. Should you wish information on how to get equipment to provide a precision Time Base for future observations, just visit my website (which you say you already have) and/or just ask.
Although time inserted video observations is state of the art nowadays, a keen team of visual observers can make highly worthwhile observations of lunar occultations and grazes, as well as asteroid occultation events.
I tool the liberty to have a look at the event circumstances based on your description. See images and .zip below. The .zip file contains a GoogleEarth.kmz file that has been adjusted for the 180m altitude of your site. Something the RASNZ info would not do. This is the old tanZ offset that had to be applied when paper maps were king. Nowadays with Occult4, a PC will crunch the numbers and provide a Kaguya Profile Prediction and link to GE with a couple of clicks.
Anyway, I wish I was there.