The thing that holds the shower head is broken. There’s a pair of flat rings with teeth that are supposed to hold the shower head up, but one of them has snapped clean in half. We’ve had to wedge the shower head behind the riser rail to stop it flopping down and linking the shower hose. When it’s in use, the water pressure keeps it in place.
I finally got fed up of it, so, buoyed up by my plumbing ‘success’ yesterday, I ordered a new riser rail from Screwfix for a tenner and replaced the old one with it. Now, the shower head stands up, seemingly all by itself, and we have to remember not to wedge it behind the rail any more.