So last week, the evening before we were due to leave for a week the bees swarmed. Only three days after they arrived. I was happily sitting in the garden when I heard a lot of bee noise and then realised that there were thousands of them close by.
Why they swarmed is not clear. Stress from the travel? Too long in nuc and overcrowding? Did not like the new hive? There were no clear queen cells that I saw before the swarm, but that does not mean that they were not there!

Fortunately they went to a low branch in a tree in the garden.
I quickly read my bee manual to find out what to do and they behaved well and were a textbook case.
I shook the swarm into the box, turned it upside down and the rest of he bees walked in so that they could find the queen.
The process was completed when I then transferred them back to the nuc.
It was certainly a steep learning curve.
A week on and the swarm in the nuc are active and I think that I have seen the queen. In the original hive the remainers are there and active. Too early to see a new queen? Next week will be instructive.