First, a note of caution. This is a *guide* you follow at your own risk. If you are in any way unsure, don't try it. If you've done a C500 or similar before, you'll have no problems.
You'll need a good torx T6, a small philips, a small flat blade scredriver and a plastic tool to prise open the case.
( I am working on the phone face down for reference to directions )
First remove the aeriel cover using the flat blade screwdriver at a 45 degree angle in the two holes either side at the top of the battery. You can leave the connector cover in but it may be easier to remove it first. When you lever the edge up, use your finger to slide the aeriel cover slightly towards the top of the phone and then pull it away.
Remoe the two torx screws under the aeriel cover, and the two at the base of the phone.
Slide your 'case opening tool' at a 45 degree upwards angle between the fascia and the black plastic chassis on the right hand side as the phone is face down. There are three clips facing 'out' and one larger one facing in so it's a bit tricky. Do the same for the other side and turn the phone over. Start to lift the right edge away, hinging on the left side, using your case opening tool. Make sure the longer case clip is clear of the screen before hinging the fascia away fully else you'll bend the plastic. If you are replacing the face don't worry too much here, just be careful you don't snap the ribbon to the keypad.
Once the face is at 90 degrees to the chassis, remove the 4 small philips holding the keypad in place and the fascia just comes away :-)
Refitting is the difficult bit :cry:
Make sure if you are fitting a new fascia, you transfer the rubber seal from around the screen surround, and also cut a bit of double sided tape to secure the speaker in place in the new face. It has a springy foam cover so it can be difficult to make stick but you do need it.
Put the keypad buttons in place and make sure they click into the locators in the frame. Press the keypad into the fascia and whilst semi-closing the fascia onto the chassis tighten the two screws near the ribbon. If slightly off centre you will chew the plastic and they won't hold. Once they're in OK check the location of the keypad is ok and put the other screws back in.
Power up the phone quickly to check all is ok with button operation.
Put the fascia directly on top of the chassis and press down hard around the edges so the plastic clips connect. Put the 4 torx screws back in, and be careful not to overtighten the top right as the plastic looks thin here and if you do it will chew out of shape and the aeriel cover won't re-fit ok.
Refit the aeriel cover and you're done