I took a look at the hive to see the progress in the box I added. Yes there was some honey! - more than I have seen from them so far.
I had added atop the hive a new box i.e. Honey Super with two new open frames. Also, I added one full frame of brood/nectar up from the box below to "seed it" (encourage them to congregate). I also added a queen excluder to temporarily separate her from the top box. I wanted to keep the queen out of top box for an attempt to get a clean sample of honeycomb without her laying eggs in it.
It wasn't apparent to me that the full frame I moved up actually had drone cells in it. I inspected the honey super (a week later) and noticed drones milling about in the top frames. This is not really a huge problem - but because they had hatched out, they are now trapped above the queen excluder. Drones are fatter than workers, like the queen, and cannot pass through the excluder to the rest of the hive. So, they're not able to leave the hive as they want to do for breeding purposes. I will soon be removing the excluder from the hive on my next visit.
I learned that various screen sizes can affect bees differently - #5 is the largest that will only allow workers through and not queens or drones. Workers can squeeze through #6 but it's a lot of work. #7 (if it's straight) will keep workers in. Also, the bottom screened boards I believe is #8 for mite traps / observation trays. But if it is damaged it could start to allow them to (almost) escape...
There is some discussion about queen excluders on honeybeesuite.com.
Next day, noon time, I added a couple plums for them to eat (last ones are just pits now left on inner cover). Later on during the day, I lifted the cover to see how the girls were enjoying the latest plums and three fat/lazy drones flew out. I bet they were happy to get out being trapped for a few days...
Inspected the bottom tray: I see two hive beetles running around - Promptly crushed!