Owain wrote:
On Nov 27, 9:25 pm, Graham. wrote:
Meter is in cupboard outside, and about two meters of tails though
the porch wall to the CU.

Depends on the DNO, but if the tails are more than 3m some insist on a
switch-fuse to provide overcurrent protection to the tails.

Isoaltor only:
http://www.tlc-direct.co.uk/Products/WYREC2S.html

I am not sure I get this bit of the link

"It's safer because the supply tails are fixed and finalised in a sealed
unit - instead of being left hanging loose ready to connect to the meter."

--
Adam