Your rights as a private buyer are reduced compared to buying from a dealer, as you only have recourse if the car was not described accurately in the advert or is unroadworthy. You can ask the seller for a full refund or a partial refund to reflect the actual condition of the vehicle, but assuming they will not agree to these options small claims court will be the only viable option. Evidencing that the vehicle was unroadworthy when you bought it is likely to be the best option as selling an unroadworthy vehicle is a criminal offence. You can read more about this here: www.honestjohn.co.uk/advice/car-buying-advice/how-.../