shame the private import scheme doesn't work like that. need to spend 1 year in the UK without leaving and prove that your moving to Australia perminately if your not an Australian resident so you have to prove that a family member that owns the car is moving to Australia.
private import only works if you move to the UK or japan for a year buy and use the car(requires rego and parking permits) it can't just sit in a shed for a year.
I'd go back to the EP3 SEVS compliance idea if i was you.

