There is enough threads and info relating to Defender TDCi (2007 - 2016, puma) clutch issues and the adaptor shaft failures, its all there part numbers and all.
*Expect the clutch to take a dump from anywhere of 70K to say 120K.
*It will rattle like a faulty gearbox on idle in neutral.
*Be aware though if the springs on the driven plate full out it often jams the whole clutch up.
*NEVER use the genuine land rover / ford clutch, heavy duty or not.
*I use ClutchFix clutches.
*Have used SACH and AP in the past which seem ok.
*Replace the slave and hydraulic fittings with the upgraded ones at the same time.

