On Wed, 02 Jan 2013 14:20:45 +0000, MM wrote:

I thought I'd hold off ordering anything until after everyone is back
from the Christmas/New Year break, so this morning I enquired at two
separate places this morning, the local family-run bathroom supplier;
and Plumb Center in Spalding.

Both told me the same thing independently of each other: Water regs
prevent swapping out two separate taps for a mixer tap/shower where the
cold water is at mains pressure, which mine is. Apparently, once the
mixer is installed, when the cold and hot are turned on, the high
pressure cold water will overwhelm the gravity-fed hot.

Water regs say that I have to run the flexible pipe for the shower head through a hole in the soap dish to prevent
water from the bath getting back up the shower. It also means you can't use the shower head to get water up
your whahoola to rinse the soap off. That is, Water regs might make sense, but sometimes only sort of.

Better (both suggested this independently): Run a new length of copper
pipe from the cold water tank in the loft to the bath and cap off the
existing mains-pressure cold supply to the bath. NB:

If you can run 22mm pipe from the tanks to the bath/shower, especially if you avoid elbows and bend the pipe
instead, this can significantly add to the flow-rate to both bath and shower.


--
Terry Fields