W
White Room
Assuming the electricians have done the job properly, and working on the basis that it's a ring main circuit with 2 wires in the back of the socket, then there's no way you'll get the faceplate through the hole in the tile. Cut the hole in the tile to the size of the backplate, take the socket off the wall, fit the tile, grout, then refit the socket. Job done
I'm no sparks but where is the earth wire which makes 3, the ring main would have wires going in and out....