Andy, Yeah, absolutely, in fact we could run a Bath that you could brew tea in (almost). It changed that night, I thought I'd got my programming wrong and had not got a full cylinder, but I've got good schedules now..
I've recently had Hive installed by British Gas, Heating is working like a Dream, Hot Water Cylinder is getting nice and Hot. HOWEVER when we run the hot tap the water initially runs Piping Hot and gets cooler over about a minute then just runs cool. If we turn the Tap off, wait about a minute...