it depends what category write off it is, cat D or C you might be able to buy back, cat B only trade can buy to break for spares tell them to find another one for sale, if they can't, surely that proves how rare they are if you have paperwork proving £10k, the insurance accepted it was worth that and charged you accordingly. if there is a dispute about value they should have questioned it when you took the policy out
the accident isn't your fault, so why should you be punished? lose your car and get a !Removed! payout too
the car should be repaired into the same condition as it was in