Many thanks. I only fitted a new inlet valve about 5 months ago, but don't remember it coming with the main's fed restrictor? I'll have a chat with my man at Screwfix.
The layout of our mains water pipework was recently changed, to move the stopcock on the incoming supply to a downstairs cupboard.
This joins a 22mm pipe that feeds upstairs cold water, and to the boiler on an unvented system. There is a tee off this 22mm pipe into a 15mm pipe which feeds the...