OK, I've spoken to people at the relevant authorities, to get the good oil. I've spoken personally to smithy and fe-ambo about this, so what follows is to assist anyone else in the same boat.
You can
apply at your local Motor Registry for an
unregistered vehicle permit. Ultimately, it would seem the provision of a permit is at the discretion of the manager of the Registry, and by no means a certainty to be endorsed. (The typical purpose of these UVPs is for seasonal use of farm machinery or moving plant equipment etc.) That approval may also require pink slip/blue slip and by extension, engineer's certification.
I've spoken to the RTA, to the Policy Section of NSW Police Traffic Branch, and to Shannons Insurance. If you have the UVP, and the vehicle is being used within the conditions set down thereon, then it's considered to be registered for all intents and purposes. You should speak to your insurer and let them know that the car is being used in this manner, to ascertain for yourself that your insurance will be honoured in the unfortunate event that you need to claim on it. Getting something from them in writing would be a very good idea.
So, long story short, if your application is approved, and you have proof of both the permit and the vehicle's insurance, that can be accepted for the purposes of participating in the Nationals.
We look forward to seeing you all there in a couple of weeks.
