We have recently moved, however we are unable to have a shower as when you turn the cold tap on it makes no difference it just comes out hotter, when you turn the hot tap off it is still boiling hot, you have to turn both taps off then the water from cold tap is cold until you turn the hot tap on , we has a plumber around whom said it needs a thermostat on the taps at a cost of �300 fitted we agreed but havent seen him since (was a month ago) so was he right? any one any ideas to fix this??? incidentally all over taps ok.