Have you ever seen a colony of feral bees?

One member wrote to me in December having spotted some in an undisclosed location in Wharfedale.  He wrote “There are lots of trees with hollows nearby, rather a puzzle why they thought 30 feet up in a beech tree under a bough a suitable permanent home. I will be watching this colony with interest through Winter and  into Spring to see whether it survives.” The email was accompanied by a picture of the feral colony: