As already covered by some of the other comments..
I also don't bother to try and crank the motor over with the starter.
A 17mm socket, t/bar on the crank is easy and if you do it in order (as per the LR manual or Haynes) you don't have to turn it far to do each one. I've trained my 12yo boy, I say "tell me to stop when No 6 is fully open" etc.
I don't remove glow plugs, why complicate a quick simple maintenance job?
If your worried about starting (how?) disconnect the battery.
The 300 TDi does have valve stem caps/clearance pads (whatever you want to call them) they should be checked for wear.
Best regards
DarrenR

