So, step one of the NatHERS report process done. Had a guy here for 3 hours (he estimated 1.5-2, but it was his first one for NSW), I've had tons of information and advice and will get an official certificate telling me how terribly insulated my house is in a day or two.
This wasn't mandatory to get done (yet), but it was discounted thanks to the NSW scheme and I now have a better informed and re-arranged set of priorities for improving the livability of my house in summer and winter.