citroen c5 fuel computer display

The button on the end of the RHS stalk that controls the centre dashboard scrolling m.p.g. / distance to go etc display appears to have worn out at 63000 miles. It was dodgey for a while, sometimes operating, sometimes not, its now given up the ghost completely.

Is there a way to repair this please (diy) , Alternatively, is there a cheaper supplier for a new stalk other than going through the citroen dealership.

Thanks