Hi, and thank you for the warm welcome.
I have built the screen shown with 4 entrances of 1 bee size. I hoped to use them to confuse the robbers, but my girls seemed to be focused on only one - so why fight em lol.
This allowed them to stop entry into the hive proper- which I had already reduced to around 4 inches.
I noticed that inside the mesh there’s 2 groups, one near the door on the bottom left and the other one opposite which were quite agitated. When I opened the entrance near them they exited and started looking for another way in.
I assumed that they had made it through the first check point, but hadn’t gotten any of the goods, hence the retry.
So now I have added a clearer I made with a swinging mesh door and attached it to the top left entrance. This seems to have settled things down behind the screen even more, as the few robbers that make it into this area are not trapped there but can escape. Also any of mine that leave this way know their way back through the other entrance. It all seems to be working out and I can see plenty of pollen laden bees entering in between fights at the door when robbers try.
I also have a bit of video footage and I will post link for that when I get home.