fwippers,
Misrepresentation requires a contract, being an agreement between two parties where one party does something in exchange for a consideration from the other party. I’ll sell you some apples and you pay me £2. There is no contract between the buyer and the car maker because the car maker doesn’t sell the buyer the car or get the money.
False or misleading advertising however doesn’t require a contract. It just has to induce someone to do something, which I guess is the sort of thing these claims companies are alleging.