wrote in message
oups.com...
Blocking up the air-brick in this weather for a short time should be
ok, and deter them if they're about to build a nest.

Too late, the nest is already fully built - and occupied with hundreds of
emerging adults daily. Trying to block the air brick could cause the wasps
to become defensive. If it were successful they'd look for other places to
leave - such as into a room.

Leave well alone.

Mary