first thing you need is a new windscreenI have retrofitted this to a 2012 Skoda Octavia so should be ok on a golfi have a mirror and RLS and loom if you are interested
I did it on my Tiguan which is the exact same system. Mk5/mk6 just have different wiring locations at the BCM.You definitely need a new windscreen with the mount already bonded, wasting your time trying to cut off he old one.