Here's a quick guide to removing the wing mirror caps, as requested by Ozi. Thanks to spinky for the spare mirrors and the help too! Sorry for the quality - phone pics...
Please note I did it with mirrors removed from the car, you should be able to use the same method if they are still attached - I won't be responsible for any breakages either way though
1. Push the mirror glass in at the side closest to the car (use the electric controls if they are still attached)
Then get you fingers behind the edge and pull fairly hard on the glass. It's clipped in quite well but comes out fine with a bit of force:

2. You will then need to remove the plug connected to the back which I believe is the heated mirror option. This just pulls out:

3 & 4. The clips are located as shown - there are 5 in total. One clip is located at the thin part near the car.
2 of the clips on mine are broken as you will see, but 3 clips still holds the cover on solidly. Make sure the plastic is not cold when you do this - they are VERY brittle. Soften them up a bit with a heat gun if you need to.

You can use a small screwdriver to push the clips off their locator tabs.
Before you try to remove the cover, bend the wing mirror inwards as if you had electric folding mirrors. (I'm not sure if you can force the electric ones as mine doesn't have that option and just push in)
Gently start to pull the cover off from the corner shown. (I'd already started flatting the paint down prior to this as you can see):

You will be left with this:

As you can see the first 2 clips are broken, but it doesn't effect them being held on.
Re fit everything in the opposite way.
Hope this is helpful to some of you!
Adam
Please note I did it with mirrors removed from the car, you should be able to use the same method if they are still attached - I won't be responsible for any breakages either way though
1. Push the mirror glass in at the side closest to the car (use the electric controls if they are still attached)
Then get you fingers behind the edge and pull fairly hard on the glass. It's clipped in quite well but comes out fine with a bit of force:

2. You will then need to remove the plug connected to the back which I believe is the heated mirror option. This just pulls out:

3 & 4. The clips are located as shown - there are 5 in total. One clip is located at the thin part near the car.
2 of the clips on mine are broken as you will see, but 3 clips still holds the cover on solidly. Make sure the plastic is not cold when you do this - they are VERY brittle. Soften them up a bit with a heat gun if you need to.

You can use a small screwdriver to push the clips off their locator tabs.
Before you try to remove the cover, bend the wing mirror inwards as if you had electric folding mirrors. (I'm not sure if you can force the electric ones as mine doesn't have that option and just push in)
Gently start to pull the cover off from the corner shown. (I'd already started flatting the paint down prior to this as you can see):

You will be left with this:

As you can see the first 2 clips are broken, but it doesn't effect them being held on.
Re fit everything in the opposite way.
Hope this is helpful to some of you!
Adam