On the basis that someone else may find this thread useful, here's an update.
I rang Vicroads this morning and they advised that the Unregistered Vehicle Permit (UVP) needed to be raised in QLD as the journey was starting there. You have to nominate start and finish address. Because of the size and mass of the trailer, they need to sight the trailer for rego and issue of plates.
So I look on the QLD Roads website, and a QLD UVP has a maximum of 7 days and costs $28pd. I queried with the Vicroads person why it had to be a QLD permit given that I would only be in QLD for 48hrs at best and their response was 'Qld permit required as that's where the journey started'.
The QLD UVP's not going to work as it is a maximum of 7 days and I'll be min 10 days before I get back to Vic.
I rang my insurance company and their only concern was that they had the VIN number and I could update the rego number when I obtained it back in Vic. So my insurance is done, but limited for onroad travel only when I have a UVP.
So now I possibly have 3 options.
1 - Go back to the idea of a 6month full QLD rego using a friends address, but my Vic Licence. This could then be cancelled and swapped over when I get back to Vic.
or
2 - Pay for a 3 day QLD UVP to drive straight back to Vic,
or
3 - take option 2, but then actually break down at Evans Head and have to camp there for a few days and then sort out either a NSW UVP, or go back to Vicroads and apply for a Vicroads UVP.
Part of my challenge here is that I'm planning a slow staggered trip back home.