we have purchased a new bedroom suite and need to move a light switch, the switch has the normal 2 wires plus the earth connected to the metal backbox, I need to move the switch so that it is on the side of the wardrobe as there is no room for it to remain on the wall, the new back box I purchased is plastic and thus has no connection available for the earth, do i just leave it connected in the metal one which will have a blanking plate over it and extend the pos/neut or do I need to look at an alternative?