Engine E70 X5 Head unit not Programmed Advise

[njoroge]

Hallow BMW Community,
I Drive a BMW X5 E70 2007, in January I had an accident the vehicle was hit from the rear end by a huge Toyota land-cruiser which damaged the entire back of the vehicle the tailgate and boot have had to be replaced.
During the accident the engine shut down it indicated Engine power failure or Engine malfunction: Reduced Power error and the car shut down it had to be towed.

Damage on the vehicle during the accident included:
1. The Tail end was completely damaged a new boot was ordered by the insurance

2. Due to the impact of the rear end the driver & passenger seats were dismounted from its position and require to be replaced as they are either damaged or the mechanism seems not to be functioning right to get them working OK.

3. Engine Shutdown explained: On diagnosis the team indicated the fuel the Fuel pump/gauges cable were damaged in the fuel tank car was the reason which was replaced and the car managed to power again after replacing of the Fuel Pump/Gauges. Which personally I didn't understand how it would have happened
After the replacement of the tail gate and diagnosis there's an error that seemingly wasn't there before the accident but the insurance company is trying to not associate it to the accident plus the local BMW Center doesn't seem to accurately point out why the fault is there or if it would have been caused by the accident
When you power on the vehicle it displays an error. “Head Unit Not Programmed Correctly”
The local BMW Center has indicated the Head Unit Requires to be replaced but the Insurance Company is not convinced this is an accident related fault. The email from BMW reads only “The defective head unit display is as a result of an internal hardware fault."
If it were a power fault as the battery area in the rear end was all messed up including the battery being loose but wasn't damaged in the impact
This explanation by the BMW Center is not good enough and I know the Insurance will not accept fault unless a concrete explanation is given which they can’t seem to know if it’s off the accident or not
Kindly help
Njoroge
Nairobi Kenya.

[X-static]

The amplifier and com box are in the rear compartments. This could easily be accident related. Possibly the communication cable between the head unit and the rear components was affected in the accident or during the related repairs.