What is catEgory d insurance loss?

From the internet: Category D - most likely to be nonstructural damage and should be relatively easily repairable. In this case the vehicle may have been economical to repair but for other reasons it was written off. For example where the insurer have to provide a courtesy car the time taken to repair the vehicle would mean that the courtesy car cost together with the repair cost would be excessive. In a category D scenario it is more likely that the insurer did not wish to repair.