Also last year, my H and I were gardening when we heard a loud buzzing noise getting louder and louder. When I looked up I saw a massive swarm heading straight for us! It was an incredible sight, mesmerising, but we rushed indoors and watched from the safety of the house! They were hovering above the greenhouse for quite a time, but luckily for us, they decided to search for a better place to set up home!
We have a local beekeeper, who sells honey, so I would have contacted them if the swarm had decided they liked the idea of setting up home in the greenhouse!