snap, my speedo has started doing just the same thing this weekend, the milage is still clocking up properly so it probably isn't the speed sensor but the clock itself.
the only consolation we have is that it is very easy to remove the instrument panel, it is held in place by two clips on itse bottom edge which you access by pulling the steering wheel adjustment out and down as far as it will go, then sliding a blunt lever (i used spoon handles!) between the instrument panel and the dash. the panel then swings out from the bottom. there is a wiring plug on the back which comes off when you push the black lever across. there are a few speedos for sale on Auto trader for arond £50.00 at the moment, (except for the 2.2 diesel auto that i've got (typical!) hope this is of some help
regards
Ron
Ron L, March 2009