Maybe a tad off-topic but I have to tell. Got called out tonight to a classic. Husband's at work so, after three weeks with no downstairs lights the missus has had enough. I arrived to find no fewer than six T & E cables dangling from a ceiling rose position. SIX!! A few questions established that one extra light had been added a couple of years ago to come on at the same time as the one that was now dismantled and dangling meacingly. (He was trying to replace the old ceiling rose) Okay, so I knew the purpose of four of the cables, but what of the other two?
Took about half an hour to hear the full story, make safe, then find and mark the original circuit and switch cabling to the light. So, three cables to go... obviously one of them must go to the additional light and be linked to switched live and neutral. I looked at the 'new' light, expecting to see a single cable. THREE all wired up as you would expect to see in a mid-circuit loop-in rose... except all three went back to the original light position. It turns out he'd looked at a couple of fittings and decided that every light must have three cables wired into it. In this case, none of the reds actually did anything at all - they just sat there, live and useless. Two of the blacks simply doubled up the neutral connection and the third black carried the switched live between the lights.
According to the missus he'd spent a couple of hours a night, ever since he'd dismantled the original connections, just connecting up every possible connection and tripping the MCB until he'd finally given up... but was too proud to call in a spark! There must be a moral in there somewhere...