Neighbours are on holiday, we know this with 100% certainty as we have the spare keys and are feeding their cats until they return on Sunday.
Yesterday evening someone started knocking quite aggressively at their door. Went on for about 15-20 minutes, DH 'popped to the shop' on the corner to get a look at them, came back and said it's definitely not a delivery, no van, guy isn't wearing any kind of uniform or holding any parcel/letter or one of their little scanners etc. Eventually they gave up and left. Now they're back (started 8:30) and knocking again!
WWYD? Ignore? Not knowing who they are we really don't want to go and start talking and give away the fact that neighbours won't be in until Sunday. We could drop neighbours a message on Whatsapp but by the time they see it it'll probably be quiet again and we don't want to worry them! I'm assuming if it was a friend of theirs they would have contacted neighbours themselves and know that they're away.
Neighbours are absolutely not the sort to be involved in anything dodgy. Middle class couple in their 30s, run their own photography business, talking about starting a family, generally very quiet and we don't really know that they're there!