Just back....... Phew, all that info from a forlorn query , again many thanks all . Gnu you sound like quite a pro. My worry, originally, (before some guys threw all those dire warnings at me, but great to have stirred up so much "vibes") was that with a bath supplied by a 1/2" mains water pipe (Town supply - good pressure and flow) to it's cold tap, and a3/4" hot water supply from a simple direct copper cylinder, I might have trouble with things like "knocking" in the cold pipe and could not combine the supplies in a "mixer" tap (Which would have to be 3/4" anyway, if only for flow rate and appearance sake. I think I will leave things as they are, it's an old place with 2ft wide external walls and the partitions not much narrower, but it is in a great location and, in case of emergencies, has a smaller bathroom/shower upstairs. How much ?? too much!

with much gratitude,

beachcomber.