Hi,
I have just replaced mine and it is easy enough to do.
If you remove the bottom of the drivers side dash to get access to the module.
Once you have taken the bottom part of the dash out look underneath and you can see a module mounted on a bracket just right of the steering column. You just need to remove 2 screws and the module comes away.
Remove the 2 plugs, replace and away you go
I got my unit from Motors in Motion scrappy for £90 delivered versus the £200 from Seat! All I had to do was re-code my keys and away I went
http://www.motorsinmotion.co.uk/
Cheers