The Natural Philosopher wrote:

Notmally the bath and basin are tee'ed into the same waste pipe as the
bog, or perhaps they are in different parts of the house? In which case
a separate vent or an air admittance valve may be required.

It's two completely separate waste pipes, one for the wc and one for the
basin and bath. Both waste pipes are long things going up above the roof
line, each vented at the top. I understand this was a common way of
doing things pre-60's.

Basically, I need to know if the basin and bath actually need to be
vented like this, or whether they can run straight into the drain,
bearing in mind they're on the ground floor.

--
Steve Loft