Liam, thanks for the compliment on the cars. Yes, I think I remember you. Yes, I was cleaning the car for my wife.
I wish I had good news, but from my experience that height is not enough. It would need to be closer to 860mm to be compliant in NSW measuring it that way. From memory our RCR seats(adjustable headrest up full) are over 900mm measuring it that way.
It's been a while since we did those type of measurements, actually a couple of years. I couldn't describe it without reading the ADR as it is complex. Maybe someone else here has looked into it more recently.