I ended up just throwing a new lock in mine a few weeks back but I still had the switch I bought before christmas from RS. This weekend I got to give it a go on my mates
Ibiza as his was playing up too.
This is the switch I used:
http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=4728308
Its by the same manufacturer as the OEM switch and has the same IP rating so wont be affected by water and dust like the maplin ones will.
Didn't get any pics due to it starting to snow just after I got the door card off which put some time pressure on!
Roughly though this is what I did:
1. Remove door card (should be a
guide for that on here somewhere)
2. Remove the ancillaries carrier (Pretty similar to this:
http://briskoda.net/forums/topic/119359-removing-the-ancillaries-carrier/?) needed a fair bit of jiggery pokery to slide it down and off.
2a. Unplug the lock mech wiring
3. Remove the lock barrel by removing the blanking grommet on the side of the door and then using a long T25 bit to undo the retaining ring.
4. Prise out the external door handle release cable.
5. Undo the spline style bolts that hold the lock mechanism in and remove from the car
6. Cut red and blue wires going to external switch half way along their length and drill out the blob rivets holding the switch in.
7. Elongate the holes which the blob rivets were in with a round needle file so that the switch can be positioned correctly
8. Attach the switch using M2 csnk machine screws and nuts with a dab of threadlock on each thread. Ensure that the heads do no stick pround of the lock chassis.
9. Extend the red and blue wires using solder and heatshrink sleaving.
10. Solder one of them to the terminal on its own on the switch and cover the connection in heat shrink.
11. Solder the other wire to the middle terminal on the switch and again cover the connection with heat shrink.
12. Cover remaining terminal with heatshrink.
13. Check that the mechanism is clear of the switch body with both the door shut and open position. (do this by sliding the mechanism with a screwdriver as if it was closing against it). If its not ok adjust the slots and switch position and re apply some thread lock if need be.
14. Start reassembling things in the reverse order of removal and testing as you go. I didn't close the door onto the striker plate, just used a screwdriver on the mech again incase I needed to get back in there.
Took about 2 hours in the end and I used:
T25 long torx bit (for lock barrell and door panel)
Cross head screw driver (for door panel)
Small flat blade screw driver (to release external door handle cable)
No 8 spline bit (For lock mech removal)
10mm socket (Ancillaries and glass removal)
Trim removal tool (for wire clip removal)
Soldering iron
Round needle file
Thread lock
Multimeter (To buzz out the old switch)
Duct tape and kitchen roll (To hold glass in place and not mark the door top when the winder mech is disconnected from the glass)
16/0.2 wire (cable extensions)
3mm heat shrink (for cable joints)
2off M2 CSNK machine screws
2off M2 nuts
Solder
Not too bad a job really. Seemed like a lot of faff compared to just putting a new lock in though. Give it a go, but if you break it you get to keep the pieces, its not my fault
Hope that helps give a bit more info anyhow...