I think you are spot on, Jacqui. It became very evident today that there are at least 2 nests in our grounds.
We got rid of one at the beginning of the season in the wall but I believe we now have one in one of the drainpipes and one under some of the decorative stones.
Think we need to go on full scale wasp attack tomorrow and drive the buggers out cos they are very, very irritating.