I've just replaced my two single bath taps with a new shower mixer tap (1/4 turn with ceramic disc, suitable for low and high pressure systems). The problem is that this new mixer tap has very poor hot water flow (takes ages to fill the bath even a small way). I have excellent hot water pressure on all other hot water taps and this was also true with the former single bath taps. Also cold water pressure seems to dominate and push back the hot water when both the hot and cold are being mixed together on the new tap. Would appreciate some advice please! Would a return valve help on the hot side or is there anything I can do to the tap valve? Or have I just got to expect this with a mixer tap? Thanks!