WTF?!
Carl, seriously, take someone who knows what they're doing with you next time you buy a car.
Spending £4k at a dealer, unless there's a very good reason not to [1],
*always* get a new MOT and *never* hand over cash until you're 100% sure it's spot on. [1] You've just negotiated £1600 off the sticker price, but no MOT due until for 12 months anyway and you've checked out the forecourt condition so are taking it as a trade sale (which I know don't technically exist, but we had a gentleman's agreement on it)