Got a combi boiler Worcester 28i Junior. Brand New. Mains pressure good tho not sure of the exact flow rate. Boiler fitted downstairs, bathroom upstairs. When the hot water is on downstairs, none comes out the hot tap upstairs in the bathroom. Understand that combi boilers have drawbacks and I know I can't put a pump in the bathroom, straight from the combi. Do I have to put a hot water tank in the loft and pump the water from there to the bathroom?