To think I shouldn't have to keep complaining about this?

[YourNewspaperIsShit]

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

I bloody wish our post man could do this. They've stopped asking our next door neighbours and its a two bus trek
to the bloody collection point. Iwannamyweddingshoes!!!!!

You- not unreasonable but they probably are asked to by your neighbours who dont have dogs.

I've not Read TFFT but how is the postie opening the window if it's on the latch? The whole point of 'night latches' is that it can't be opened from the out side!

I once left my window opened and this happened. It knocked over an ornament. Great.

No nickname we had to prove we had taken "reasonable" steps to make sure that he couldn't get out and attack someone. The burglar was more than determined to break in and did a lot of damage doing so. We had a sign "Beware rottweiler running free" so he knew the dog was there and was shocked when he was attacked

I would never leave my windows open if nobody is home.
I shop online a lot and always get emails from the delivery companies asking me to provide a safe place to leave parcel if I'm not at home.
I either nominate a neighbour or ask them to leave it somewhere in my garden.
I would never leave windows open .
That is Madness and asking for trouble and your house insurance would become invalid if you left windows open on purpose and informed delivery companies of that.

Lick up and the issue disappears

The postman was trying to be helpful in a place where it's standard practice to leave doors unlocked and gets four complaints! That's why my postman isnt anywhere near as helpfulas yours. Because he had a problem customer before too. It's these kind of things that sap the goodwill and joy out of doing a job and everyone ends us suffering. No good deed goes unpunished, as they say

"I would never leave my windows open if nobody is home."

What about the upstairs windows? A burglar would have to climb up a ladder in full view of your neighbours to get in via an upstairs window, unless the drain pipe is scalable. I've left the small bathroom window open a few times as only a small child could get through there.

Legally, even if a door or window is unlocked and on a latch, opening the door or window is defined as "breaking and entering".
The PO seems to think it can do what it likes so the OP needs to lock her windows and doors if she's out.
Round here (largish town) our beef is that the the postmen (not seemingly the women) don't leave a card when they are unable to deliver a parcel. Sometimes the parcel is returned to the depot and sometimes left with a neighbour but the addressee has no way of knowing. Without a card the parcel cannot be picked up from the depot. Without a card you don't know it's been left with a neighbour and not all neighbours bring it round -- some wait for it to be collected.
PO says workers made a note to say a card was left and refuses to apologise