I found one of these the other day in my Kitchen. From a distance it looked and sounded like a blue bottle. When it landed on the kettle I was going to whack it with the newspaper, then saw that it was a black bee with a deep orange tail stripe. So I shooed it outside and didn't think anything else about it until I saw this post.
Then today I decided that it was an auspicious time to screw two eye hooks into the mysterious big holes that a previous owner had drilled into the stone lintel over the door, so that I could train my honey-suckle over the door. Just as I was about to a bee whizzed out of the hole and then another poked it's head out to have a look. So now I'm hoping that I might get a little colony in the wall cavity.