Thanks for this. Phone successfully fixed! Just an additional note for people, I noticed my replacement part was missing a lot of the grey gaskets. There are a few of these under both boards, a few small square ones, and a very thin windy one under the bottom board. Not sure if required but I transferred these across to my new one using some tweezers to very carefully peel them off. Make sure you get the "glue" bit underneath to come up at the same time if you can, otherwise you may need extra glue to reattach them. Be careful transferring the volume buttons too, they need to be carefully taken off in the same way and reattached to the new one.

Wow, that was a mission! I didn't have any isopropyl alcohol which i'm assuming makes it much harder. Make sure you have that before starting I guess. I used a hairdryer to heat the front of the screen, but even then it was a long job. It is properly glued in there!! Just take your time. I had a flexible piece of plastic which I managed to eventually get under the battery and just slowly worked round underneath to free it up, whilst pulling on top of the battery with a suction cup. Good luck!!!

The back cover was a little tricky, I found the top left was the part of the case that I got to open first, then you can run a plastic tool around all the sides.

At this step, what I assume is a proximity sensor also came away, and was attached to the underside of the metal plate. You can see it in the picture as a second square piece of metal to the right of the battery connector. This got in the way a little bit, but was just about able to remove (and reattach) the battery connector without trying to remove it from the plate.