A friend of mine that kept bees before the mite got here had 30 plus colonies. When the mite came, he lost all but one. He never treated for anything, with anything. He just harvested honey and caught swarms. No management of any kind.
He started catching swarms from the one surviving colony. In 2002 he gave me a swarm from one of the 5 hives he had at that time. That colony is the strongest one I have today. I have never treated it nor it's descendants. I have caught swarms, made splits, ETC. to multiply that colony. All the people I have let have that strain of bees have been happy with them. Some of those people are also leaving them without treatments.
There were no controlled breeding, just survival of the fittest.
Can queens be shipped from the US to the UK? I have no idea.