Hi I think the subject explains most of what I'm looking to do. I need to add a double socket and the best place for the cable is the wall cavity. The socket is on an exernal wall on the ground floor whichhas floorboards. The wall cavity is insulated but not with polystyrene balls. Apart from the various rules saying it's an undesirable situation, are there any tips to accomplish said task? Was going to drill at a downward angle into the cavity from where the socket will be, and hope to pick up the cable into a hole into the cavity under floorboard level. I was intending to have a bigger diameter hole under the floor and use a hook to pull the cable through, assuming it ever feeds into the right location! Could protect holes to avoid damaging cable when pulling through. Any other tips? Ta.