Thanks for getting back Bahco.
Here's a bigger picture, should have posted it before:
It connects behind the diverter valve which switches between the riser rail and the hose and is the thing at the front. The on/off valve is on the left of that and the thermostat on the right...
Evening,
We've had a Triton Capella mixer shower part-installed. It's been plumbed in as far as the diverter valve, but they left the riser rail and showerhead off so I could tile and then fit the rail.
When I've gone to do this it doesn't look like it's going to work. The manual talks...