I think if they are bumble bees, then I will have a look at getting a beekeeper (or someone or something along the lines of that) to have a look at them and maybe take them away to somewhere where they are safer.
Since NSC knows most things...
We were moving some garden waste to the bottom of our garden, then I started to see some bees flying around, I poked the pile of garden waste and some more came out, but not many, I then used a shovel to see if there was a hive, I didn't see one, but at least 15...