That's a VERY good price for an 04 TDCi!

There shouldn't be many problems at that sort of mileage but just make sure it's not billlowing out smoke from cold start as sometimes the injectors develop a problem [and it's not cheap to fix]. Obviously it shouldn't leave a plume of any colour smoke as you accelerate hard, same with any car.

The only other MAIN problem on those is the dual mass fly wheel which is expensive to replace, if there's a kind of "whizzing" noise [like something is loose, metal on metal] when the cars started, walk away... I'm sure someone will be able to explain that experience better but it's early and I'm half asleep If you've driven it though and you're happy? Gearboxes on these should be tight and the clutch should be what most people describe as "sudden".

And at that price from a trader [I'm not being funny or over dramatic] check with Experian/Hpi that it's not been involved in any accidents!