Agreed with Martin, cat b's can get logbooks and can can back on the road, but not many insurance companies would pay out on a cat b again, but they probably would happily insure you.

Also you can export CAT B's, the HPi register is UK only i.e a cat b car here wont be a cat b car aboard, and to re register a car in some euro countries you only really need the export certifcate hence why the price of breakers have shot through the roof because of the polish lituahians turks etc