Tools required: Torx 3 screwdriver, plastic tool such as a guitar plectrum or credit card.
Open the flip then slide your plastic tool around the edge of the plastic lens to remove it.
Your phone should now look like below. Remove the four screws you can see. Note that the two at the bottom are black and the two at the top are silver and these need to go back in the right place as they're slightly different lengths.
Run your plastic tool around the join of the top cover in order to release it.
Your phone should now look like below.
Your phone should now look like below. Lever the screen out at the points circled below.
You should now have the screen removed.
Slide your plastic tool behind the small screen to separate it from the large screen. You'll need some double sided tape to stick this back down.
You should now have both screens removed. Reverse the whole procedure for reassembly.