For a while now I have had problems with my 04 1.9 cdti (120) starting - it would always start but needed a lot of cranking before it would fire. When turning the key the starter always sounded sluggish as though the battery was getting low - put a new battery on and had replaced the alternator a few months before but still had the problem. Reading another post, another member (Steve19cdti) had said that he had similar problems and had replaced his starter motor and had cured the poor starting. I decided to replace mine - right pig of a job - but since changing it, it now starts at the first turn of the key and turns the engine over a lot faster hence the better starting. The old motor looked ok but had a lot of wear and movement in the end bearing at the toothed gear end, which was obviously affecting the performance of the motor. Right pia changing the motor but obviously worthwhile if you are having starting problems
Thanks again to Steve for the advice