Sorry to hear that Andy, hope you recover soon.
Located the source of the leak - fortunately it's just a connection from the header tank. It was dripping down onto the hot water tank, pooling on the floor beneath (all in a cupboard upstairs), then dripping through the ceiling. Done a temporary repair with PTFE tape, and should have a new connection fitted later this week.
Great, no need to rip out a ceiling, or floor or whatever!