I think you are very wise phoning the police and your solicitor, assuming this is a Ford dealer; I think you should also call Ford HQ and speak to customer services.
Personally I think I would push for a new car, if the damage they are repairing is their entire fault and as bad as it sounds and nothing to do with you I certainly would not except the car back.
If you have the car on finance I think I would contact them and your insurance company – basically talk to all involved.
Oh and while you are at it name and shame the dealer.