Hi Sean,
There is a small screw in the centre of the 'winder' which you can loosen to check out the spring underneath it.
I seem to recall that you can pull the winder to adjust the clock too, but our Fulvia is too far away from me to check this right now.
Perhaps the winder isn't engaging the shaft?
But I wouldn't suggest removing the whole dashboard to get at the clock - just the veneer and the two black panels adjacent to the clock. Anyway, the clock fitted to our car is virtually a sealed unit - the silver bezel on the face is crimped over on the clock body.
Our clock can be set, but only runs intermittently even though the electrical supply is constant.
Regards,
Guy