Robo you may indeed be right but i think it may well be a combination of causes rather than one in particular.
In the morning it was speculation and now it is a fact. :P
associates nationwide have noticed is that even 1 year old queens are trying to swarm
It is very normal that 1-y queens swarm.
In Finland 2 summer ago we had awfull swarming summer. It was rainy weather which was the reason and early good spring in westtend part. Hives developed well.
If you have got carniolan blood in UK it is good to swarm. Of course German black is even worse and you perhaps have plenty of those pure nature beekeepers which like "feral bee stocks". Swarming is natural habit.
If you take daughters from swarm hives you surely get swarms.
or the bees are trying to supersede a lot more in his opinion.
This is difficult question without carefull data. "Time polishes memories".
In my opinion queens have been better and better. Insemination is one reason fot that. I am worried about desease tolerance.