From the pictures it can be clearly seen that the mushroom fixing was incorrectly used and caused the lights in the house to fail. The insulation was fitted approx 5 years ago, but the fault only came to light recently. We had to cut out the insulation. Then we had to chase out the wall, remove the Mushroom fixing and repair the cable. Cables should be run vertically or horizontally and all trades should know this. The cables in this instance were run vertically and were properly installed.