Remove all the screws on the door itself then use a thin level under the plastic cover either side of the locking clip that extrudes from the inside of the door. Gently lever the cover off. When putting back on, put the cover in place at the opposite side of the locking clip first and press the rest of it down firmly working towards the locking clip.
To remove the inserts: use the lever on the inside and the inserts will pop up. I'd advise removing only one as the hinge can be easily installed in the door with one in the door and the other placed on the hinge before securing to the door again. Bit fiddly.
SU, November 2005