my brother was involved in an accident 8 months ago...a driver smashed into the back of his work lorry ,,inside weree him and his work mate...my brother hurt his back so got a claim in,his workmate didnt...the cops arrived at scene and didnt take names or anything as no one was hurt there and then,my brother took the other drivers name and details went back to the yard and gave them to his boss...apparently the boss said it was ok to let the other party pay for the damage to truck tailgate lights etc...the other car was badly smashed....anyway 8 months on and my brother has a solicitors letter saying that they cannot locate the other drivers details as my bothers old company has ceased to operate and shut down 5 months ago so no way of contacting them...my brother has photos of the whole smash including the other drivers registration details,,,surely his lawyer could trace the car from them pics,,the pics show in great detail everything and other driver obviously admitted fault at the scene to police and him...his workmate has giving statement to lawyer allready about the incident....
I'd be very surprised if the Police, after turning up, didn't at least check the reg. numbers of the vehicles to ensure they were insured, taxed and mot'd. All of this information is on the Police National Computer / DVLA database.
This sounds like your brother's solicitor could do a lot more. If you have reg numbers or details of the police who attended then more information is definitely available.
If your brother has photos of the other driver's registration details, the Solicitor should be able to trace the other driver's insurance company and policy number through a MIDIS search (Motor Insurers Database Information Service) which Solicitors can access to check that Third Party's have insurance in place. The Letter of Claim can be sent direct to the Insurers provided enough detail about the circumstances of the accident are provided so that they can trace the same.
I'm surprised that your brother's solicitor hasn't gone down this route though. Hope it helps.