This is how it is as I'm building it.
I now know the water is seeping through the wall. Had to pull out the small cabinet though to find that. Good timing - I think another few weeks and the cabinet would have started to break up at the bottom.
Charming isn't it? I find it disgusting to be frank but onwards and upwards. Made a call to a local plumber who hasn't replied but that's good: now I think I can do it myself so will save money. I'll cut the pipe and knock it out of the wall and have a look. Will wait for it all to dry then cement the floor and lay tiles to the wall (found some spare of the same) then repair all the edges, put new pipe in and cement all around. Looking for a second-hand vanity and will paint the wall first and seal whatever is necessary. Whilst shifting the sink unit outside the base collapsed which means there has been a leak there for some time.
OK. Now I'm a bit more relaxed think I might go ahead and paint the second guest bedroom that was on my agenda for next week. I'll buy the bits I need and see if I can fix sooner rather than later but will go ahead with the bedroom whilst it dries here and loses the damp smell.