hard water

Hi, I have a MIRA JUMP electric shower and about twice a year the TCO Cut switch blows and this is basically because the shower head has gotten clogged due to hard water. Unfortunately I don't live at the property all the time and the lodger fails to tell me that the shower head is clogged...

I live in a very hard water area. I want to find a solution to this and looked at several ways. 1 fit an inline water conditioner for the whole house, such as limetron £170 , stuart Turner £150 , combicare £40 +25 each year for new cartridges. 2 water softener unit £600 , but I dont have the...