hi I’ve recently turned the water back on in the house and suddenly it stopped flowing. It stopped in the kitchen first. After messing about with taps it came back on in the kitchen and has now transferred to the first floor bathroom where it has lost pressure, although improved a bit after some messing about with taps. There is loud water hammer from the hot in this room. The top floor bathroom above is just fine. I have single leaver mixer taps for basins and baths in both bathrooms. Any help massively appreciated as it’s driving me mad.