MARK HARDACRE
If it's a light switch just wire it to the earth terminal on the back box the metal screws that fix the switch to the back box complete the connection. If it's your sockets then run an earth from the back box to the earth terminal on the rear of the socket. Most sockets now have earth running plate to the patress screw locations, so there is no need to earth the back box have a look on the rear of your sockets to find out. 'If in doubt call us out'
