I think there has been some confusion in this thread. I believe if the vehicle is registered as yours, yet you insure your parent as the main driver, then that is illegal. However if the vehicle is registered as your parents, you can then use them as the main driver and you as a named driver, but I doubt it would be cheaper, insurance companies have clicked onto things like that (they have also clicked onto people buying vans and insuring them as traders vehicles). I often see people talking on pistonheads on apparently series 3 landrover defenders are apparently quite cheap to insure? Might be worth looking into?