Buying a 'nice' low/reasonable mileage diesel is gonna be an expensive proposition. You could always buy a cheaper petrol and spend the money on fuel -pay as you go, rather than tying up big money in a diesel (which you don't really want).
Coming at you from Left field in no particular order
Nissan Maxima -Jap reliability, comfy, leather with toys, -cheap. 2L V6 so you' still be welcome in FTO circles
http://www.carzone.ie/search/Nissan/Max ... annel=CARS (I'd offer about 50% of the asking price)
and a bit more realistic
http://www.carzone.ie/search/Nissan/Max ... annel=CARS
Mazda Zedos 9, (see above) quite rare and Nicer looking IMO than the Maxima. Definitely a buyers market for these things.
http://www.carzone.ie/search/Mazda/Xedo ... annel=CARS
And how could we forget the daddy of Jap barges -the Camry. Un breakable. Will probably out last you -and can be passed on to your grand children as an inheritance!
http://www.carzone.ie/search/Toyota/Cam ... annel=CARS
http://www.carzone.ie/search/Toyota/Cam ... annel=CARS