The message
from Mike Halmarack ... contains these words:

occurs naturally up there via the eaves but I do know that with an
airbrick in each opposing gable wall, there's a pretty constant and
very noticeable breeze. Do you notice much air movement if you stick
your head above the parapet?

Ah, it's a terrace so there's no way of having a vent in the dividing
wall - unless I want to smell nextdoor's fags even more than I already
do.

--
Skipweasel
Pay no attention to that man behind the curtain.