Insurance cannot take responsibility for damage to my wall

A few months ago, a car drove off the road and smashed into my front wall at home. As it was quite a severe accident, the police arrived at the scene and took all the details of the driver and issued me with those details as well as a reference number to submit to my insurance. I then heard back from my insurance that they were unable to get in touch with the driver of the vehicle and asked me to get in contact with him and get his insurance details. So I made a visit to his house (the details the police gave me) and was told that he had moved months ago. I told this to the insurance company and they said that without the correct insurance details etc. I would have to cover the repair of the wall myself or through them (therefore raising my insurance premium). The police will not even entertain my requests for details of the driver.

What can I do?