Is it true that category D insurance write off cars do not have the fact that they have been subject to an insurance write off on their registration documents?
yes, the thing is that insurance wise one dent can cause a write off if the car is getting on a bit, so cat D means it's not finacially viable to repair but still safe to drive.
Off subject a little and not likely to put anyone's mind at rest but a car could have had a huge smash and been rebuilt on a cash payment, no insurance claim so no record. The only way to be sure about any car is to have a professional, physical check.
Having said that, cat 'D' should be or been repaired well enough to be safe but no record is on the V5.