suspicious insurance repair costs

My dad is a taxi driver and was involved in an accident that wasn't his fault. Somebody hit him from behind on the motorway a421. The driver left the scene without the car before the police arrived.



The insurance initially said that the driver wasn't insured because the car that hit my dad was stolen so my dad to claim off his own insurance. Now we were told that they are going to claim of the others guys insurance because the insurance was made on the same day of the accident.



Today when we spoke to them they said the cost to repair the vehicle is around 7000 pounds. I find this very strange because the car is a 2016 Mercedes's e class AMG night edition.



The damage is at the right back side of the vehicle and also in the front right side because my dad went into the barrier. The van that hit my dad was doing around 80 mph . The back left tyre exploded as well.


I find it very strange that the cost to repair is only 7 thousand and me and my dad are worried that it the car won't be fixed properly. (Possible not genuine parts )



We were thinking to do it ourselves if they give us the money but they said they would charge us storage costs , possible orders already made and evaluation fee, the insurance guy refused to give an estimate. He also refused to give the evaluation report to us.



My dad was involved in another accident with a very Passat 2012 around 2 years ago and it was barely scratched . The evaluation was 4000 pounds. How is it possible then that a 2016 Mercedes's e class that's quite visibly damaged be only 7000 pounds.



I'm not very knowledgeable when it comes to laws so what I want to know is , what can we do to make sure the car is done properly? Can we request a Mercedes official evaluator to see if the car is going to be fixed properly ?

Can we get another evaluation from another garage independently? Is it normal that they don't want to show us the evaluation report ?


Any advice will be greatly appreciated