It means a claim has been intimated by a previous policyholder and it has then been cancelled. This could mean it was a notification for information purposes only, or the owner claimed directly through the other party's insurance. Certainly have the car inspected prior to purchase, ask the seller the direct question "has this vehicle ever been involved in an accident". They have no duty to inform you if not questioned, but have to answer by law. You can cancel without loosing your deposit under the Consumer Act 2015 which gives a 14 day period. If you have provided a deposit on credit card, you are also protected by the Consumer Credit Act 2006. If you are concerned or worried, if the vehicle is not as fit for purpose as described or of merchantable quality, walk away.