If going for the BMW based 2.5TD, seriously consider a manual. The TD + Auto box is a poor combination, and not particularly economical. TBH, I found my 3.0l V6 petrol cheaper to run than my 2.5TD auto, by the time servicing costs were taken into account.
The manual is better suited.
People get it in their head that because it says "BMW" on it, it must be the best thing since sliced bread. Its not. I quite like the engine, but they are fragile, especially if they have been abused in a former life (they all have, as nobody obeyed the 4500 mile service interval). The pumps are tempremental as well, as are most similar Bosch pumps, and expensive to replace.
But don't let me put you off - its not a bad engine. Just get the BMW thing out of your head. And get a manual.
The 2.2DTi is a GM lump, and produces similar power, and slightly better economy, and is only available with a manual.