Does anyone know how to remove the headrests. I've just got some new trim and can't for the life of me get them to budge.

Unclip the seat back trim at the bottom - can be fiddly but once it starts to move its easy enough. Slide the trim up over the seat until you can see the headrest stem - use a screwdriver to push the detent spring out of the way in the headrest stem - its on the left near the bottom.