"If it has never been right you don't need a new cartridge. You can tweak the cartridge inside which is held on by four screws. You take out the screws and turn the dial inside a 1/4 of a turn more towards the hot.
Hard to explain but you can "commission" these showers to get them hotter."...
"is it a recent problem or has it always been wrong?"
Noticed it last winter when I really needed hot showers. In the summer I don't mind so much but yes I guess it's always like that
"if you turn the shower down (slower flow, not colder) does it get warmer?"
No
"You probably...
I had a Gainsborough GS500 mixed shower installed 2 years ago as part of a
bathroom refit. I have a combination boiler and the water is mains fed.
The boiler is working perfectly well - I have checked at all the hot water
taps and the temperature is fine. However, when I run a shower...