I did this the other week. I thinks it's quite easy if I remember rightly. The switch is fitted into that plastic panel that becomes the handle for pulling the door shut. There is a join that runs down the handle and back to the door card (joins the padded or fabric arm rest). If you carefully slide a flat head screwdriver into that join the top half of the door handle panel with start to pop up. You can then grab hold of it and pull it off. The lecty window switch is clipped into that panel and the wires plug into the switch. Easy peasy! Only problem is that changing the switch hasn't improved the window operation much

. I even sprayed everything with a liberal dose of electrical contact cleaner

. Apparently there is some wiring that is quite a common fail on the mk3's that needs replacing to revive the window properly.
Maybe someone else can help with that?
