Broken shower

[Scarlett]

I have posted this in "How it works", apologies if I should not have, I wasn't sure of the category!!
My shower regularly breaks. The pressure switch breaks and cold water ends up flowing through the unit, out the bottom and trips the switch. I turn it off at the power and get the man out to fix it. He fits a new switch, which lasts 4 months, and then it happens again.
Should I just get a new shower- and if so, what is a good type? I think the pressure switch is continually breaking cos the bathroom is in a low pressure area (?) so I have to have the dial on nearly full, and full power, to get the water hot enough. Is this pushing the unit to it's limits? Help!