plumber's unable to source leak, help, bathroom into living room

[Jude Henderson]

I have a leak from the bathroom into my living room directly below. I cut the bulge and even cut a hole in the ceiling to try and locate the problem and ultimately allow the water to drain out. This has been going on for at least two weeks. I initially had a plumber out to fix the toilet cistern as it seemed to be leaking and causing the floor to get wet. As soon as this was fixed the water started leaking from the ceiling. Surely this isn't just a coincidence to have two plumbing problems one after another?!
I have had two different plumbers out who have both been unable to locate the source of the leak and just leave. I am still stuck with water draining into my living room.
It seems to leak largely in the morning. It does stop for long periods. It doesn't corelate to me flushing the toilet or using the shower.
Grateful for any advice on what to do/where to turn.

 

[Chuck]

It would be worth casting a careful eye over the cistern. It might still be leaking but the water is now running down a new path that is less visible. Next up, check along the supply pipe to the cistern. It's possible that it was disturbed during the original repair and a joint was cracked.

Or it could just be coincidence.

 

[Deleted member 120897]

How big is the hole you cut? I would make it bigger (unless already big) and have a look with a torch for any indication of where it might be coming from.