Never mind, fixed it now. Made a web page with pictures
maybe this might help someone in the future, who knows. Perhaps it could be relevant to owners of Golfs/Leons/so-on and so-forth. It's free hosting thing, so dunno how long it'll stay up there though.
Cheers.
Problem: Windscreen wiper fault on a Skoda Octavia. May also apply to VW Golfs and other similar cars.
Symptoms: Window wipers wouldn't stop readily once started. Occasionally would stop in the middle of the window. Most common that the windscreen wipers just kept going for a minute or so.
Fault found: Relay contact covered in sticky gunge. Could explain why the symptoms were worse when the car was cold - stickyness more at lower temperatures? Something like that anyway.
Solution: Clean sticky gunge off (obviously) very carefully (even more obviously).
Time taken: Three hours. This include going to a shop to buy relevant screwdrivers, making a sausage butty & cup of tea and shouting at the Jeremy Vine phone in on Radio 2. So all in all, probably a 45 minute job.
1) Remove the trim around the speedometer. On the top surface of this trim, there are two screws behind coverings. Remove the screws, pull forward and detach from dashboard. The cloth that covers the extending steering column is attached to this bit, but just pulls off easily.
2) Remove screws from dash, noting the three screws in the footwell and especially the 'hidden' screw behind the trim of the headlight switch.
3) To remove headlight switch, detach fuse panel (screws highlighted in green) and push hand through hole. With the headlight switch in the off position, push in and turn to the right, this will release the catches and release the switch body. Pull out and detach wires from the back. On the headlight unit level-dial, feel around the back and unclip the switch, push through, detach the wires. Pull trim out, noting the four plastic catches. You may need to make a tool to release the one above the circular hole, I used a cut-to-shape ring-pull from a tin of peaches. Very high tech. This releases the trim and reveals the 'hidden' screw. Undo it.
4) The dash should now pull out. Don't pull too far forward, the diagnostics port will still be attached. Don't put too much strain on these wires, support the dash in some way to prevent excess strain (I couldn't be bothered to work out how to take the diagnostic port out, sorry).
5) Look to the right hand side of the relay board, the big relay is the wiper control unit. Gently pull it out.
6) Remove the black plastic casing.
7) Look for any sticky gunge on the relay contacts.
8) Clean. I used a small piece of card that I'd stripped from a laminated card box. This gave a thin but relatively rough surface with which to remove the gunge from the relay contacts. Now all you have to do is put everything back together again, which is easy as it's just the reversal of disassembly.
9) Test it, it should be much better. Should be - I can't guarantee anything. Worked for me though.