This is the 4th time I've rang Royal Mail for the exact same complaint and it's been two different houses although not sure how many different postmen.
They keep opening windows and doors to put my parcels inside if I don't answer
The most recent one I nipped out and left my windows on the latch but the door locked, I was due a Glossybox so it was obvious to the postman what it was (not important) and I always collect them from the delivery office after a missed delivery. When I came home it was on my sofa (under the latched window).
I have a big dog and 4 house cats who fortunately did not attack him or escape.
Every time I complain they agree it's out of order and say they will pass the complaint on but clearly no-one is listening 