Do you have a Bentley manual?
I changed these exact same light (driver's side) on a friend's golf a few months ago - and was quite simple, I thought.
There's a vanity cover with a little light bulb molded into the plastic - held by two screws. Remove two screws and pull off the cover - that's how I got to the holder... Removing the battery and tray could be helpful if your hands are big or like/need a little more space....
Unless you have to remove the headlamp assembly for another reason, I didn't see any reason to go through all that o.0