button on end of rear wash wipe that controls on board computer won't work ?

on my Picasso 1.8 exclusive the button on the steering column that controls/scrolls through options for the on-board computer display ( right hand section of the dash display ) has stopped working (annoyingly stuck on the overspeed warning). The rear wash wipe stalk has this button on the end of it - everything else works OK. Citroen dealer option is to fit a complete stalk array on the steering column !! Very expensive ! Any ideas ?