Sorry for scuppering that deal

Insurance companies like to assume the position of power in the event of claims, acting as if they are being very charitable in their offer in your time of need. However the owner of the car is in a real position of power.
Many people also believe they have to have their car repaired at the insurance companies chosen bodyshop, which again is not the case, even if it says so in the small print.
The motor insurance cat database was originally put together to protect the public from written off cars getting back on the road, in particular cat A and cat B cars. Cat C and D are just markers for the insurance companies discression. So in particular when the damage is minor and should not effect any future buyer of the car being ripped off or exposed to a dangerous repair, they are not obliged to place the marker on the car, so if it will close a file, which they are negotiating to close (irritating if you do not accept their offers) they will jump at it in a flash.
I have saved lots of members and customers cars over the years with this and by producing valuations as well.
Once a marker is there though, it is much harder to remove. Also a catC or catD effectively will reduce the value of the car in the insurance companies eyes by around 25% for future claims, so it is worth making sure the car is not listed.
I personally am not put off by cat-c and cat-d cars, especially if it is possible to research the history of the claim. Two of my old 968 Club Sports were cat-c's. One had minor damage to a rear quarter from the 1990's which was a cat-c because the owner refused to use a direct line approved bodyshop, so he took the insurance money and took it to porsche (I would have helped him get the money without the marker if I was involved) and was listed as a cat-c because the insurance company could not comfirm it had been repaired. the other was a cat-c because it was stolen, the insurance company paid out before it was found, marked it as a cat-c and stolen, then it turned up.. so the insurance company removed the stolen marker but could not remove the cat-c marker, no damage other than to the door lock and steering lock.. Not exactly a hazard to the buying public in either case.
I would estimate that a large number of Porsche are cat-c or cat-d at some point in their history for very similar reasons (not wanting to use the insurance companies bodyshop, wanting a specialist or OPC to repair, or through the car being stolen and not turning up until after the insurance company paid out.