Dave Starling wrote:

Rainwater into the sewage system isn't great from the point of view of
the water company. Older properties would discharge rainwater to the
sewers, but post 1950's built houses should drain gutters to a
soakaway. If you had any sort of extension build, then BC would insist
on soakaways.

Soakaways aren't permitted within 5m of a building, and they have never been
insisted upon by anyone at any time, least of all BC.
You are thinking of a dual system, and the rainwater doesn't go to a
soakaway, it goes to a stream, river, ditch or similar, to save unnecesary
treatment of what is basically fresh water



Why don't you divert the rain into a large tank and use it for
flushing loo/watering.
As a plus point if you are on water meter then you won't pay to flush/
dispose of your Richard III's.

He might save a bit of metered water, but he'll still have to pay up for the
turd treatment


--
Phil L
RSRL Tipster Of The Year 2008