I have a 2003 2.5 CRD Limited Edition and have had a similar issue with one of my mirrors. First thing is to check the fuse of course. If you can fold them in by hand without any great resistance it may be that they have been replaced at some stage..also, can you hear any electric motor sound when you flick the fold switch? If not, and the fuses are all intact, pop the door card/panel off and have a look at the wiring connection....if there are seven wires going from the connecter to the mirror, it's the real deal, however if there's only three wires then it's a manual fold. You can check the current flow from the rocker switch to the connecter while you have it open.
Just as a guide, the proper electric all singing, all dancing mirror will cost you around 320 quid each, but the manual folding, heated, adjustable version from Devon 4x4 or similar places 85-90 quid.
Give all that a try and see how ya go.
