An AA inspection found an oil leak in my new car - how do I guarantee the dealer fix it before buying?

I'm buying a 2012 Ford Mondeo Estate from a trade dealer. Before committing I decided to have an AA inspection. The inspection found oil on the lower engine cover so I've asked the dealer to have a look and they said they've sorted it. How should I go about checking they have actually sorted it and are not just saying that?
Make them commit in writing to have fixed all the faults that the AA found, on penalty of giving you a full refund, and do not buy the car until they have signed a piece of paper to that effect.
Answered by Honest John on

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