"Aidan" wrote in message
om...
I also thought it might be Equator, PEX.

I'd do all the connection in Equator. The advantage over copper is
that it won't split if it should freeze. I'd mortar a 22mm copper pipe
sleeve into the wall, pack the space between the two pipes with
insulation material and mastic it in.

You'd probably need a double-check valve, to prevent the contents of
your hose, pond, paddling pool, etc., being syphoned back into the
mains if the pressure should fail. Anyone care to quote chapter &
verse of the relevant regulations?

You are right. A double check valve is needed. Some taps now have them
built-in.