I once had a similar situation where I had a person reverse into my old GC8 and drive off. Luckily a car yard provided me the rego and description of car and driver. My insurance company wanted to charge me an excess for the claim and so I gave them a choice of charging me an excess when making the claim and me moving all of my insurances or to protect my no claim bonus, not charge any cost and retain me as a customer. I am still with the same insurer.