Hope the purchase goes well. Agree with all above re stone chips with that mileage you might expect 3-4 max on the frontal area. I'd be suprised if you had much more than that, and no big defects. I have lots of tiny specs on the front of the rear arches.
Running cost wise I get about 27-28mpg with normal driving Personal best is about 34mpg or 9.6mpg depending on perspective. Worth checking if the car comes already with the Service Inclusive Package. You get the free servicing for 5 years or 60,000 miles. For brake wear, go into the Nav Menu - Vehicle Information, look for Car Status in the menus. It will tell you when oil, brakes and next service are due. Should be 15k miles for service, approx 25k miles for brakes. Much less than that and it would suggest its been thrashed!
Either way they are bloody tough cars so enjoy! With the DTC fully on! You may spin in MDM, you will spin with it all off.