NT wrote:
Its entirely pointless, unless of course you run a lot of large loads
upstairs, for reasons I cant imagine.

Splitting the ring into 2x 20A circuits doesn't gain you anything
much, and only worsens its safety performance.

The only place your average 2 bed house would benefit from a 2nd ring
is the kitchen, where the heavy loads live. But even then, as you
already know, in practice one can run a whole house on a single ring.

We've got a similar problem in that we have solid floors downstairs so
all of the ring mains will need to run in the suspended ceilings. The
trouble being that there is a 50m cable length limit on the ring main,
and you use up about 4.5m each socket coming down from the ceiling then
back up.

Unfortunately the windows come too low down on the wall to run across
underneath them, and there are doors/chimney breasts to get in the way
as well.

I was thinking it might be possible to run a thick cable out to some
kind of junction box, then spurs out to each socket rather than a ring -
I don't know if that's allowed under the wiring regs?