My recent no-fault crunch and the book value of the car leaves me in the position that the car will be automatically Cat-C'd *again* and I still won't receive the cost of repairs... not a happy bunny.
A few years ago my immaculate BXGTi was damaged by some hoarding around a building site collapsing onto it whilst the car was parked in the street.
The builders accepted liability, but wanted me to use their chosen repairer.
I refused and took it up with my insurers who agreed that it should be repaired even though the cost of repair exceeded the value of the car.
The car was repaired, I paid the excess which was refunded to me by my insurers once they had collected from the builders insurance.
The log book remained unstamped as a cat D write off or anything.
It put me back in the position where I was before the accident happened.
I don't see why your damage should be treated any differently.