Personally, with a car this small, I would rather have a petrol engine, as it should still have reasonable fuel economy. Petrol engines are nicer and easier to maintain. You don't get much fuel economy benefit from a diesel with a small car, and that's the only reason to buy diesel in my opinion.
Common things to go wrong in diesels are fuel injectors, engine management sensors, possibly clutch. If something is wrong, bigger bill potential. Detailed info for car at:
honestjohn.co.uk
parkers.co.uk