Sometimes, when plumbing, it's best to go in the back way. Installing a new electric shower this week. The brass fittings on the existing pipe would not fit the push fit entry point on the new shower. Rather than destroy the lovely tile work, I cut a section of wall out on the landing behind. Once the plumbing was done, the section could be refit and patched up. Finished plaster work to follow. See if you can tell where it was done.