Well, I got stuck into the car today as I need to get it running for work tomorrow.
The culprit is the lock cylinder (between the ignition barrel and the ignition switch), the small tab which turns the switch has broken off inside the cylinder and doesn't turn the switch anymore.
Here's a link if anyone needs it in the future:
VWVortex.com - HOWTO replace mk4 ignition lock cylinder?
I haven't replaced the cylinder yet, as the security bolts holding it on to the column need to be ground off. I'll source a new cylinder next week. At the moment I'm using a small screwdriver to start the car with the key installed to turn off the immobiliser.
Cheers
Bookmarks