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2) today I re-dumped as many as I could into the nuc and set the entrance to Qx, low and behold many of the bees left outside have actually gone inside now. There's probably less that 25% left bearding on the front so space again maybe?
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5) I'm assuming the Q is in the nuc as most of the stragglers have now entered of their own free will. ...
6) I've moved the nuc far to a new location and will check the ground tomorrow when it's light. ...
Once Q is inside, the rest will follow.
Normally, the swarms I catch are a few miles from my apiary, so, when I take them 'home' they need to reorientate to the new location. (Yes there is valid reason to take unknown swarms to an isolation apiary until proven healthy ...)
What I was suggesting regarding moving your box, was just moving it
a couple of feet, so that you could tell whether stragglers were rejoining the box, or a bunch on the grass where the nuc had been previously (and where Q might then still be).
But because they are rejoining the nuc, no need to make any shift of the box. If you shift the nuc more than a few feet, you will be bleeding off some bees that won't identify where their swarm group has gone.
Bees performing Nasonov-fanning headstands at the entrance is a brilliant indicator of Q being inside. If you don't know what to look for, take a look at
https://www.youtube.com/watch?v=a7Dl1CtSihc
The 'fanners' are putting up a scent trail to "call in" the rest of the swarm to their new home.
They don't need to do it after everyone has found where she is ... so they don't keep doing it for days after moving in.
My interpretation of your reports is that Q was underneath the nuc, and you only got her inside at your second "dumping" attempt.
Let them settle and draw some comb.
Once they have moved in, open the QX entrance. Until then, keep checking that it hasn't become blocked by Drones trapped inside (yes, swarms have some Drones caught up in the general excitement).
Being a small entrance it is easily blocked.
Feeding.
Normally, you shouldn't feed for 3 days after swarming.
Or right after hiving (you could be refuelling them to abscond).
However, after sitting outside your nuc for a couple of days, this lot ain't going anywhere and will need feeding swiftly.
Starting now and continuing even after hiving them in a full hive, you should maintain a supply of 50/50 syrup and shuffle and turn frames to get a whole brood box of frames beautifully, quickly and completely drawn.
A swarm is a comb-making machine. But they'll stop (and not restart) if
either they are satisfied that their comb is adequate for now
or the 'flow' of syrup/nectar stops. (Don't let the feeder go empty!)