The stalk arrived today. (I bought it on Thursday night, so that was pretty good.) It is different to the one my D8 406 had. The one on the D8 moved forwards/backwards and up/down. This one has five buttons and a thumb wheel.
The plastic cover on the steering column has two torx screws up the bottom of it. Furtunately I found a flat blade screwdriver that fitted. (There is a square hole in the middle of the back edge of the bottom plastic -- what is this for?) Typically, re-fitting it was the hardest part of the job.
The new stalk plugged straight into the hole. Strangely, there was this blanking plate in there:
The electrical connection automatically mates as you shove the stalk into the hole -- I thought this was quite a neat design.
