Our new bathroom has not only involved updating and replumbing a lot of the hot and cold water system, but also a relook at the central heating controls. When we moved in, we were surprised that whatever we did to the thermostat heating was an all or nothing affair. Surprised that is until Dh took the controls apart and realised it hadn’t been wired into the system! The heating controls tho are old fashioned and pretty inaccessible so Dh has moved and upgraded them 
Oh and here is what the plumbing to the loft looks like – shiny
It is going to be hidden by a stud wall, and the shower is going to go in front. Also a stud wall on the other side of the bathroom as easier apparently than making good. will loose perhaps 10cm from room by these 2 combined, but should be OK. I was hoping for the bathroom to be finished before christmas camp, but a bit concerned now, as all the preliminary work has taken so long. But it is definitely best to build our bathroom on a solid footing