Difficult to answer without knowing the price of the car and your expectations of the vehicle. High-mileage diesels can hit 250,000 miles but you will have to spend a lot of money to keep the car on the road as key components wear out. And at 156,000 miles, things will wear out very quickly. For example, a new exhaust gas recirculation (EGR) Valve will set you back a minimum of £800. The full service history is a positive sign, but the cam belt should ideally be changed every 60,000 miles or five years (which means it may need doing again very soon) at a cost of £400+.