Quick update # 2.
Above my wardrobe, on the other side of the hole is indeed my neighbours bathroom. There had been a minor leak there a couple of weeks ago. This leak was apparently somehow caused by a cleaner de-laminating he vinyl flooring doing a homer, thus uninsured.
The leak had just resulted in some staining on the ceiling in my wardrobe and source of leak rectified by neighbour.
Neighbour has had builders in today to rip out his old bathroom to get it redone. Builder’s mate has forgotten that he was not on the ground floor and tried to stand on plasterboard.
Turns out the firm in doing the work is neighbour’s cousins cat’s friends or some other link.
Neighbour has called his insurance co and an assessor is coming tomorrow to assess.
In short the problem was (apparently) initially caused by an uninsured person. A rookie co has then been called in to rectify but in doing so has made the issue far worse. Now neighbour is hoping insurance will cover it.
I suspect this is going to turn into one major ball ache.