First and foremost, if you want to retain your car then do not under any circumstances let the insurance company or their representative take it away. Even if you make a claim against their insurer, you have a right to retain the salvage and should ask for this to be considered as part of your settlement. As your car is likely to be Cat N (which means the damage is non-structural) there is no reason why it can't be repaired safely, but the marker will remain with the car for life and it will be worth less than an uncategorised car.