These wasps have made a nest on the brick wall under a window sill. The nest looks like a grey and black beehive about the size of a cricket ball.
Should I be concerned about them?
Thank you for your help! The nest is under a second story window frame so they are fine where they are, I don't think we need to mess about with their house. I'm interested in the different nest shape you describe, these ones have made a shape like a ball smooshed onto the bricks with kind of honeycomb like chambers. I can't get a photo because it's too high up and the zoom on my phone is rubbish!
Those links are really cool, thank you! I have had another look at the nest and I think the way the wasps have built it , kind of wedged up under the window sill, makes it look kind of like a ball of playdo squashed under the sill. I'm guessing the anchor stalk is hidden from view and the shape is like the second link image. Thanks again for your information.