Hi
These are certainly the newly arrived bumblebee
Bombus hypnorum. I am collecting data to help monitor the spread of these beautiful bees (
BWARS Home Page) across the UK and I would really welcome the full "who, when and where" information (pm me would be fine).
These are very short season bumblebees and will be nearing the end of their life cycles shortly. The nests are usually vacated by the end of June... so if you can leave them where they are it would be better. They are very unlikely to be a threat to you, your family or pets.
Hope this helps
Best wishes, Stuart