You will be a rating 6 and judged as not ever having insurance.
It's stupid, I was in the same situation, I even got a my insurer (GIO) to provide a written statement that I was rating 2, driving 4 years, no claims, but it was not accepted due to the technicality that I was not "the policy holder".
However, if you've had insurance in your own name (even third party) then most companies will give you some kind of NCB - which I think is a bit stupid... people with 3rd party don't normally claim so if they've had an accident the insurer doesn't even know, but if you have full comp you would normally claim.