system is gravity fed hot tank in airing cuboard and tank is directly above it about a foot between them,Hot taps are really slow,these are bristan low pressure taps so i dont think this is the problem,ive tried the cold to hot washer hose trick to clear air still same.The valve thats in the pipe from the tank to the hot water tank when shut totally stops any hot water flowing at all,at a loss as to what to try next apart from raising cold tank into loft or fitting a pump.Any assistence much appreciated.