Hi Ian,You've not said whether the shower is electric or not.If it is the latter and was like my Mira 723 you need to take off the press in front cover/cap to reveal a screw which you undo and reposition the plastic outer temp.selection ring/controller in the position you are trying to direct the temparature;it,s on a splined shaft,only move it a small amount at a time to avoid over compensating.
Good luck Richard
Richard Martin
January 2009