Is the garage legally allowed to do this?

Joe_Horner

Try to get the offer in writing (or at least email) first along wih some sort of admission of their mistake.

The easiest way to do that would probably be to email them wih a brief summary of what happened (including the 'van being menioned) and asking them to email back with confirmation of their offer so your parents can "consider" it. If they don't argue with the summary of the facts in their reply then they're effectively agreeing with them. Obviously, after "considering" for a day or so your parents will decide to reject the offer

That way, if it does have to be taken further, it'll be much harder for them to suddenly claim that the caravan wasn't mentioned.

System

Yes my father should have checked himself but they are not very internet savvy and hence asked the salesman.

But you do not need to be internet savvy to check the weight plate on a vehicle. I would think that a caravan owner would know more about that side of things than a car salesman