Firstly, is your car a total loss? If the repair costs are less than the market value, it is not a total loss. You can either insist it is repaired or request a cash in lieu settlement. Doing either of these things stops them from placing a categorisation on the vehicle. If the repair costs are more than the market value, then the car is a total loss and will have a category put on it. Contact the insurer and request a 'full engineers version of their Audatex estimate', not a summary version as this shows very little by way of information. You need this to identify what the repair costs are relative to the value of the vehicle. Where the repair costs are more than the value, Cat N is about 26% of the market value. If the repair cost are less than the market value, you are looking at 35%. Do not agree to this if the repair costs are less than the market value.