After a month or so of me having Karen's second-hand bath water every night we finally got the shower back in use last week and I can stop worrying about how much hot water we're using each day.
The shower we went for has enclosed controls and a fixed 8" head sticking out of the wall above, which makes it a bit like standing in a monsoon. Here the controls panel:
Couldn't be simpler could it. It's not even as complicated as it might look. You turn it one way for on and the other for off. The further you turn it in the on direction the warmer it gets. Unscrew for hot. Screw for off.
There's a reason I wanted a simple shower control and that stems from using overly-complicated showers when visiting other people's houses. You know the ones? It's the normally the electric shower variety that have not only an on/off button and temperature control but also a hi/lo control. The idea of it all makes sense but the practice is never so simple. Half the time in somebody elses shower is normally spent trying to get less than a trickle at anything other than freezing or scaulding.
You can always bet the shower's owner knows exactly which combination of settings gets the best results and could probably show you how to achieve this. However, I'd like not to have to show people how to use the shower. A shower shouldn't need a demo and I'm happy ours doesn't.