You have to have shown that the bulk of the repair or significant effort and cost has been put into the repair.
Think about it.
The test is to ensure written off and damaged cars are not ringed and different bodies etc are used to repair them.

If you haven't even started the repair, you could simply buy a car damaged, go for a vic test, then go away and ring the car as you intended anyway
So although they can't stop it, all they try to see is that you have put time, effort and money into the repair so are less likely to go away and ring it.