If you are in an area where lime scale is a problem you may need to de-scale
the shower control. I don't know how easy that would be on the shower that
you have but on mine, I turned off the water to it, drained it, then filled
it with a 50% solution of vinegar (about 4 ounces), and left it for 30
minutes. Result - good as new.
I have a Gainsborough 200x shower that has decided to mess me about.
To get hot water out of it I have to turn the dial all the way to hot
but the flow of water is very poor, if I leave the setting at a good
flow rate the shower is cold.
Any idea's ? Or should I just fork out £45 for a new shower