Was the check done a vehicle identity check? This does not lift a marker, it only validates that the vehicle is what it pertains to be. Did you have a HPI check done prior to purchase? As a Category B, the vehicle should not be on the road and should have been scrapped. Your can contact the DVLA and ask them to contact the Motor Insurance Anti-Fraud Theft Register (MIAFTA) to advise a clerical error has been made and the vehicle should have been a Cat C, rather than Cat B. It will be very, very doubtful they will do this. If anything, it does not change the fact that the vehicle may well be unsafe and should not be on the road. The only other option to try and legally do something is to contact Autolign Inspections (www.autolign.co.uk) and explain the situation. They can usually only remove previous total loss markers that are not Cat B or Cat A. So, again, the chances are very slim. It sounds like you've been majorly conned.