Now i've been fortunate enough to have previously opened a fair few of these using the widely published method of having the router upside down with the back towards you and pushing the the front two feet away from you. Now on more than one occasion I've managed to break or bend plastic and clips so came up with my own way of doing it and not had any breakages yet.

Place the router on it's side on a flat surface and put the palm of your hand and thumb in between the the legs and gently push until a small gap is created between the blue facia and black casing.

Next insert a small flat head screwdriver between the facia and body

Next gently move the handle of the screwdriver towards the rear of the router which will open the gap all the way down

Then simply 'unhinge' the facia away from the body