Is it... or isn't it a Bombus hypnorum?

Yesterday I heard plenty of buzzing and saw about 15 Bumblebees on this Horse Chestnut Tree: A great source of neactar and pollen to a variety of bee species.

There were loads of Bombus lapidarius (Red Tailed Bumblebee), lots of Bombus terrestris (Buff Tailed Bumblebee) and several Bombus pascuorums (Common Carder Bee) sniffing around too, but I only had my iphone on me.

So today I kept my camera handy and just managed to capture this shot, way up in the tree, of what I think is my first sighting of a Bombus hypnorum (The Tree Bumblebee). Although it probably should have a whiter bottom.

It could be a large, darker haired version of the Bombus pascuorum though.

Can you help?