Make sure it has a good service history. Suspension should need a good looking over. get them to turn the car on (if it doesn't turn over first go the battery could be on the way out, or starter motor, etc etc), stick your head in the engine bay and listen for any ticking or odd sounds . If you can, crawl under the car and look for signs of leaking fluids from the transmission, steering rack boots, and so on. Dunno, other than that get it checked by your local RAC if you're in doubt. And as you have said, high kilometres are risky. If it has been looked after impeccably you could be okay, otherwise it could need a new engine or rebuild down the track.