TR-03Mark the position and check what's behind the wallHold the ring at the height you want, mark the screw holes with a pencil, and check they're level using a spirit level. Run a detector over the marked spots, but treat this as a guide, not proof — detectors miss cables that are deep, in metal conduit, or outside the usual safe zones near sockets and switches. Avoid drilling directly above or below sockets, and stay clear of any pipework you can see or hear behind the wall.