We fitted the solar hot water cylinder and the pump station in the bathroom. All the pipes are concealed inside a stud wall.
The controller is mounted in an opening in the wall along with some of the control valves. This way everything can be enclosed so the electrics are "not technically in the bathroom", but the controller is still accessible from the landing to see what the hot water temperature is.
The controller is a pump station from Resol. It combines a control panel, up to four temperature sensor inputs, a pump, a spare relay output, a flow meter, a pressure gauge, a non-return valve, a pressure relief valve, a port for the expansion vessel and fill and drain ports. The manual is a ghastly translation from German but the unit itself seems well made and so far trouble free. Below the controller you can see the thermostatic mixing valve.