How does the new law affect vehicles for which third parties are insured to drive?

If you are one of the few who can drive any other vehicle with the owner's permission (3rd party only basis) with their own insurance policy. The other vehicle must still be insured in its own right to be on the road legally. To be driven on the road your dad's camper van must be insured. If you then drive it you are covered to do so by your insurance, the camper van isn't, so it must have its own.