How do you enable mirror dip?
Paul: you live in Ireland (what a fantastic country!), so you have a "Rest of World" model Golf (not a "North American Region" model). Then it's more likely that you will have memory module in your passenger side mirror (I'd be surprised if your GTI doesn't have this module).
So there are two things that you need to do; You first need to enable the facility, then you need to adjust the mirror position
To see if your car has mirror-dip do this:
1. With the car's ignition turned-on, press the CAR button on the RHS of the media head
2. Press the screen panel that says "setup" (it's on the bottom LHS and it has a symbol of a gear)
3. Press the screen panel that says " mirrors and windows"
4. Under the "mirror" section of the next screen, you will an entry that says something like "dip in reverse" if you have the correct module. If you have it, put a tick in the box next to the entry.
5. Exit all the screens
To adjust the mirror to the correct position do this:
1. Turn-on the ignition
2. Put the mirror position knob to "L" (i.e. passenger side for those of us that drive on the correct side of the road - haha)
3. Select reverse gear
4. Adjust the mirror to the correct position so that you can see the kerb near the rear wheel.
5. LEAVE THE MIRROR KNOB ON "L"
6. Take the gear out of reverse (I think that the mirror returns to the normal position at this point)
That's it. Now what should happen is that every time that you select reverse, the mirror will automatically go to the position that you set and the mirror will return to the normal position when the car is moving forward at about 5 km/h (but remember to leave the mirror knob on "L").