Hi all, My bath/shower diverter 'knob' has become so tight I can no longer pull it up to use the shower. I've tried descaling it with vinegar with no luck so I think it needs replacing. However I'm stuck as how to replace it. Is it an easy job? I really can't afford to replace the taps if it will be easy replace the valve. Do I need to remove the taps though to remove the valve? Thanks, I'd appreciate any suggestions.