Hey folks, long story short, we moved in to our house just before Christmas, part of the job that was being done was the upstairs bathroom having a new toilet/sink suite as well as a new shower cubicle + tray. We originally had a quadrant style, but either the plumber didn't fit it right, or the part was faulty, but the doors didn't close properly, so the bathroom place refunded it, and we swapped it out for a standard square cubicle and tray. Anyhow, we had the ceilings skimmed, as they were artex, this was done prior to the bathroom fitting, and I did notice, once the shower work was done, a small crack in the ceiling, very fine, but we thought it was possibly due to the banging and hammering whilst fitting the new suite above it must have caused a stress crack on the ceiling. Anyhow, fast forward a few weeks and I saw this; Water... So I went to the bathroom the next day, and checked sealing around the tray, there was one place I notice did not have any sealant, so I sealed it, and monitored the next few days of use, no more water... Now, fast forward to yesterday evening, I notice, not more water, but that the crack itself has gotten a lot bigger, almost like someones used a pencil on the ceiling, it's spreading out almost into a V shape. It doesn't feel damp to the touch, but there is movement if I press it up a bit, you can see the water stain is still there but that's just from before, I would hazard a guess it would stain the ceiling until painted anyway? I have a couple of suspicions it's either a leaking shower tray, leaking pipe or poorly fitted tray, if the tray was poorly fitted could it cause the ceiling to buckle/crack under the stress of it? The obvious thing to do would be get a plasterer in to cut that ceiling part out and check from underneath, but as it had artex originally underneath it, and it's a 70's house, I would 99% assume it has asbestos in the artex, and am not really keen on the idea of someone just cutting it, especially as we have a young child in the house too. Taking the tray out and looking from the top, would be a lot more involved though, so it does seem it may be the only option - debating a call to my home insurance as well?