Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
G.C. Number 47 075 01
Outer case
Unscrew the two fixing screws on the sides of the chassis, and remove the outer case.
Lower Door Panel
Gently remove the lower door panel off its hinges.
Air Box
Release the six 1/4 turn screws securing the airbox door panel and remove the door.
Combustion Box
Undo the four screws securing the combustion box door and remove the door.