Basically I just want to know what is required to fit a sensor in my bathroom and do away with the light switch completely. I'm having a new stud wall built with a pocket siding door inside the wall. So the joiner said I'd need to get a pull down light switch so there would be no wires in the wall where the door wood be inside a metal frame. I don't like the idea of a pull down and prefer the sensor . Any advice would be grateful , I'm not an electrician but surely if I switch the mains off it wouldn't be a big job??? The other wire that runs down the wall is going to the thermostat on the pics, that has to be removed to .... thanks