Thanks. If only I had looked on Forum earlier. I've had an hour of swearing and bemoaning my lot. I never thought that it was a Thames Water fault because I had a very similar and inexplicable problem with the upstairs cold water taps 5 days ago, which then inexplicably healed itself. So I assumed that maybe the problem had just migrated. Oh well, at least I have cleaned out the aerator on the kitchen tap now. (I don't know what that is for, but there it is).
David Ainsworth ● 874d