While you wait for answers, we may have found some information which could help you.
Click here for Shower Head Replacegainsborough sv 800?
Gainsborough 8.5e ?
Gainsborough 2000x leaking from bottom of copper cylinder ?
what KW is my Gainsborough ps1200 power shower as I need to replace it? Any?
Gainsborough 2000x shower?
Gainsborough 8.5 se hot/ cold water problems ?