You can either make him the main driver on one of the vehicles and have the policy in his name, or contact future insurers to see if they will consider your shared claims history to credit his no claims. Admiral do this on some of their policies. Buying a banger and insuring it is a novel way round it and nothing to say you cannot, it just appears a very expensive way round it. You could insure him on a policy for a few months and cancel it, then request current proof of no claims. But you would then have cancellation fees. Your best out of all would be to insure him as the main user on the A5.