With a lot of Googling I've found loads of different things that could be causing this - and none for a Ford Transit so I hope someone can explain exactly what is causing this problem, and from the mechanical side, what is actually physically happening, (and how the mechanism actually works).
Often when I try to go into first gear, the stick does not go all the way in, and it makes a grinding sound. It seems worse when the van is at a stand still - it goes in far more easily when the van is rolling slightly (a few mph). If I depress and repress the clutch, sometimes it goes in, but can take 3-4 attempts at times. The reverse gear has the same problem, but I have not tried it while rolling forward or backwards, since it's not all that easy!
The model is a 2005 2.0L Diesel SWB.
What part is likely to be needing repair? Perhaps someone can give a link to an example part? For example: