Am I obliged to accept a third party's insurance company write-off decision?

While parked outside her home, a friend's car was damaged by a supermarket delivery van. The driver admitted responsibility and left a number to call to follow up. The supermarket's insurer have handled it and offered to obtain a quote from their repairers. They have now come back saying its uneconomic to repair, stating they are duty bound to register the car as a write off.
The damage was very minor: scratches and a small dent on a wheel arch. The car is quite old and probably worth only £1000-1500 but I'm fairly sure it could be repaired for about £250-300 in a local body shop.
Is the insurer correct in asserting the car must be registered a write off (Cat D presumably)?
Is my friend free to seek a second opinion, ignore the damage or make alternative arrangements to avoid the Cat D? (which I assume will reduce the value of the car when she comes to sell).
The car has been returned to my friend and is perfectly drivable.

Asked on 5 June 2015 by Gaz14

Answered by Honest John
They are not 'DUTY BOUND' to register the car as a write off unless you give your permission. Tell them that if they write it off you will demand an exact replacement. You will not accept 'market value' and you believe that you are being made the subject of a scam which you will take up with the FCA. Seek the help of timkelly@motorclaimguru.co.uk
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