In article ,
Jack wrote:
I'm a little concerned about the mixture of hot-water (=corrosion), mains
voltage and bathrooms.

In terms of corrosion, etc, surely it's no different than having an
immersion as a back up in most gas fired systems which use a storage tank?

How safe are these installations, what special safeguards do they need
and what level of professional qualification do I need to look for in an
installer. In particular, can these devices generally be safely
installed by corgi registered plumbers as part of the refurbishment or
do we need to get in an electrician?

Well, I'd not trust the average CORGI type to change the battery in a
torch, electricity wise.

--
*Monday is an awful way to spend 1/7th of your life *

Dave Plowman London SW 12
RIP Acorn