I've just replaced mine. I have a mk1.5 but I'm pretty sure it's the same. What you need to do is:
1. unplug the wiring form the back of the bulb.
2. find the top of the clip above the bulb connection.
3. push the clip in and to the left on the right headlamp (passenger side) or in and to the right on the drivers side.
4. the clip should now be released so pull out the old bulb
5. insert the new bulb
6. put the clip back into place (reversal of removal
) making sure it has clipped in and is nicely secure
7. re-connect the wiring.
I mine I really had to push down quite hard on the clip to release it, which does hurt, especially when you have cold fingers. Hope this helps