Just wanted to say thank you for the take apart and walk through. Very comprehensive, even for a noob like me I was able to complete it under 2hrs. Just taking my time to ensure I didn't strip any bolts, or break any clips.
Things I have learnt from doing it.
Initial trim comes off easily, can be a little tricky in the last step putting it back on, as you need to align the plastic trim pieces to plastic grooves in the door skin I think. If you apply it and it doesn't look like it is sitting flush and aligned with the panel, pull it off again and ensure the the black plastic lips on the trim piece sit under the teeth on the door panel.
Enusre all your bolts are laid out correctly, I used an old egg carton to keep them in order. As they do differ in size and you can possibly damage the door skin or thread if a long bolt is placed in a short thread.
Was initially confused how to remove the door handle, but pulling it away out of the mechanism then out does work. The arrows were a little confusing.
White plastic shroud sitting over the mechanism inside was initially hard to remove, but just pry it out. It does have internal clips which fasten to the mechanism and are tough, so hopefully you can't break them too easily.
Ensure you remember to remove the bits you need from the old mechaniism, and completely agree about testing it out before reassembling the entire door. Once you do have it fitted with the MBit screws to the door, you can close the door or use the central locking to test if everything is working correctly.
Applying the door skin on your own can be tricky, but can be done. Make sure you get the alignment right. There are some black plasic knobs near the screw points to assist in ensuring that the door skin is aligned correctly. Also, test fit all the screws in for alignment first before screwing it down permanently just to ensure everything is aligned correctly.
Thanks again for the HOW TO, definitely feels good to work on your own car and fix it. Especially when the specialist wanted £90 to fit the part. No thank you!