Fortunately, according to the Haynes Manual, its located behind the glovebox so all thats required is to unscrew the couple of bottom mounting screws, withdraw the glovebox and there it is. Then disconnect the lead to it and unscrew the two screws holding it in and its removed.
Fingers crossed now that the fault is that component and that it won't cost too much (yes, I know the latter is hoping for a lot!!).
Stephen, July 2009