typical hmrc really leave it slightly ambiguous so they can swoop in and say ah but, and we want the money back lol. thats why so much stuff ends up going to court for a definative answer.
it does leave open the option for a close relative to buy and register a car in their name otherwise why ask for the additional info. but also would you if your not disabled have to pay the road fund. etc.
as ever as clear as mud. keep us informed if you get better info from the dealer glosguy its an interesting one.