Begs the question of how you're measuring it. Basic physics tells us
there will be a v drop.

No it doesn't. The OP is not indulging in petitio principii. It might
raise the question, but it doesn't beg it.

And to sound off on ring circuits vis-a-vis radials: weren't rings in
part devised to cope with post-WW2 copper shortages - wouldn't it be
'greener' to continue using rings as radial usage would increase
copper usage.

And another thing...with all the campaigning to minimise the use of
'standby' rather than physically 'off' switches, and encourage people
to unplug mobile phone chargers and the suchlike when not in use,
won't the requirements for RCDs significantly increase base-load power
consumption? All the RCDs I've come across dissipate a few watts.
Replacing all the rewireable fuses in my consumer unit with RCBOs; or
indeed replacing sockets with ones that have RCD protection build in
will increase consumption.

Regards,

Sid