The overpayment will make sense if you are incurring extra costs to transport the car (and agreed on these expenses with the buyer). But the lack of details about the buyer is a big red flag - you should have their name, address and telephone number.

Overpayments can be innocent or part of a scam. Usually, when it comes to fraud, the buyer will overpay for a car and then ask for you to repay the extra money. This will be requested via a 'wired' transfer by a third-party company.

In the event of a scam, the buyer will cancel the cheque after you've made the transfer and keep the 'overpayment' money and vanish (there is little recourse with wire payments).

If the overpayment is valid (and covers agreed additional expenses) then pay the cheque into your account and keep the car until the funds have been cleared.

If the overpayment is not valid, get the buyer's details and return the cheque. You can then ask the buyer to send you another cheque for the correct amount. If they refuse or try to pressure you into accepting more money than agreed, cancel the deal.