The Natural Philosopher wrote:
Never forget the howl of anguish from a teenager upstairs, having a
shower, when I the visitor, tried to wash my hands in the downstairs loo..

Ah, you should've used the hand wash basin...

Anyway, after a week of fiddling about crawling under
the kitchen sink and wandering back and forth to
and from the bathroom, I've got something acceptable.
Shower runs at 45 degrees at slightly lower flow than
I prefer, but still usable. Another advantage is that
the cold water doesn't go bouncing out of the kitchen
sink any more. Takes 9 seconds to fill a 1.5l kettle.

Will have to mark the main stop cock tap somehow
so if it gets moved I can reset it fairly easily.

JGH