NDT, I'm from just south of Edinburgh, with a VCDS (Vag-Com) cable. Want me to scan your car sometime? From that you'll be able to see the part number for everything installed on your car (including radio) and take it from there.
Are you looking to upgrade your head unit, or simply add an iPod lead?
The iPod lead/dock simulates a CD changer so you can have 6 playlists (not sure how it chooses them). With newer head units the MDI dock connects your iPhone/iPod and charges it (like the iPod lead/dock) but gives you full control from the head unit.
Gimme a PM if you wanna meet up sometime. Cheers