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Short story is this: glow plug warning light keeps flashing, brake lights don't work. Went to Euro Car Parts and bought a brake light switch for a tenner, wrong part it seems (all done in a hurry, as the wife uses the car for work)
The problem I have is that there seems to be two switches above the break pedal. The first one is a white one that looks like this
http://media.mister-auto.com/fae/brake- ... 4280-1.jpg
and there is a second switch along - its purpose I am yet to establish.
From what i could see both switches do nothing else but make an on/off connection for the two wires that feed it, so I left the switch depressed hoping to see the brake lights on, but that didnt happen.
I also checked the fuse and it's fine. Could it be that both brake light bulbs went off? But that doesn't explain the glow plug warning light flashing (by the way if I turn the engine on, it takes about half a minute or so before the glow light starts to flash)
Has anyone got any more info on how to fix this problem? Any insight is greatly appreciated.

I've been on the phone with the local VW dealer parts department and they have kindly confirmed the part numbers:
The break light switch is: 6k0945515A

Then it comes the misterious blue switch, whose part number it appears to be 1H0907343

http://www.ebay.co.uk/itm/Audi-Seat-Sko ... 1c2832f1ff
After much digging and with the help of a german speaking work colleague, it looks like this second switch is for cruise control (GRA in german). I haven't got cruise control, so hopefully replacing only the brake light switch (standard) should solve the problem.
I'll update this thread as I progress for the benefit of anyone else who may need this info

Second one is a vacuum switch and yes, looks to be for cruise control. Probably a standard fit item regardless of spec.

alexperkins wrote:Second one is a vacuum switch and yes, looks to be for cruise control. Probably a standard fit item regardless of spec.

I've checked the voltage on the connector to this vacuum switch and it looks like there is current coming through. Wonder if this vacuum switch might also affect the brake lights?!

(Note that this part 1H0907343 might appear in the VW catalogue as "ventilation valve" - the vw guy was just as mystified as I was)

I would think that switch stays energized till the brake pedal is pressed braking the circuit and releasing the vaccuum

That isnt related to the brakes - its to do with vacuum for other features

all sorted - it was the break light switch. (note to myself: get the multimeter out before going into panic mode about parts and stuff...)