My nephew's car suffered body and wheel damage while it was left for a routine service at a garage. He noticed the damage when he was collecting the car, and although they didn't deny the damage happened while on the premises they said they couldn't claim liability because of their insurance. The service people had not advised him of the damage when he collected the keys. The garage said they didn't know whether it had happened during the service or whether another vehicle had collided with it. They did, however, give him a signed piece of paper saying they would pay for the damage. He refused to take the car off their premises so the garage gave him a replacement vehicle until the damage was repaired. They admitted that the vehicle was undamaged when he had left it with them. Should my nephew inform his insurance company?