Mr Goat -
According to my old (spare) pulley, a collection of bolts as supplied in the DiffLock puller kit, and my thread gauges.........
M6 (13MM A/F Head size) X 1.25 MM pitch............
There you go.
Ahhhhh, nuts - just noticed its a 200Tdi - sorry cant help - above info is for my 300TDi :'(