Bees in hole in ground

Hi
I’ve just spotted an amazing number of bumble bees (like at least fifty!) buzzing around a small hole in the garden near the sweet peas. All fighting and scrambling to get into the small hole which is the size of a broom handle.
These are really large bumble bees and as soon as I get near the sweet peas they buzz furiously around my head trying to scare me off - they are blooming well succeeding!
Obviously I am thrilled to have these beautiful creatures in the garden, but I am worried about getting stung -plus how am I going to pick the sweet peas?.
I’ve put a wire cage around them to keep Fitzroy (the puss away from them).
The photo doesn’t come near to showing the number of airborne ones. No exaggeration when I say at least fifty!