Avoid it like the plague. Never trust a dealer unless there are photographs of the vehicle before and after, estimate/engineers reports for what was required and copies of the invoices for parts fitted plus evidence that the vehicle has been repaired back to the original equipment manufacturers standard. A Cat C is a write off where the repair cost exceeded the market value - it would take more than a bonnet and side panel to do that. You have also advised that it is a Cat S. The car cannot be both. Cat S means the car has had structural damage. Why would you want to buy a car that has had structural damage? I would not even bother looking at it. Buy a car that has not been a total loss, much safer.