You're probably right about their access but a) wasps are anything but
stupid except that b) they can't read English.

Seal the gap under the skirting! It will help with draughtproofing too.

Mary

Unfortunately I just put down some of that laminated wooden floor
stuff and you have to leave a gap to allow the spiders and wasp
in...er, I mean to allow the floor to float around the room.

p.s. the ones that couldn't find their way out after coming in might
be slightly stupid imho...