What is the difference between the 09' and 10' diesels

[AshD_UK]

I'm getting my first first BMW in the way of a 118D. I have a budget of 9-10K and up till now have been looking at the 2010 models with about 50K miles on the clock.

I've noticed if I go for a 2009 model, they're quite a bit cheaper so I can one with 20k miles less for the same money.

Is there any difference in the two, engine or anything else? is it better to go for an 09' with 30k miles or 10' with 50k miles??