we have a combi boiler (Wickes) worked well almost for first year, heats about 10 radiators throughout the house. Problem is the hot water. When running a bath we are having to trickle the water at a snails pace in order for it to be hot, we shouldn't have to do this surely, what are we doing wrong and how can we remedy the problem, it takes for ever to run a hot bath, the radiators are fine no problem with heating whatsoever it is just the slow hot water, if we boost the tap then it runs out cold....help