I work for a leasing company and we aren’t allowed to touch driving schools, because according to our asset valuation/remarketing teams, they are basically a bag of nails once the instructor is done with the car.
It’s one of them, it could be absolutely fine and you get a few years of trouble free motoring out of it, but equally with that kind of mileage on it, if you get a major failure it’s likely to cost a fortune and you’ll be looking at paying 50%+ of the value to get it back on the road. The other issue is, with a car having covered that amount of mileage, major repairs tend to lead to other issues and it can be a right nightmare when that happens.
I’d ask if they can send you photos of the service history, but also ask if they have the full repair history too (warranty items, major repairs, brake changes, clutch replacement MOT history, etc etc)