Yep they're bees!
Some challenge, but not too much. They can't all be as easy as that last one I did!
They are in the wall of a bungalow at the end of a cul de sac with a bung wall on the right and the neighbour's brick wall on the left. Hopefully they are only in the one section of the wall. If they extend around the corner to the neighbour's side It will be extremely difficult to access that section of the nest. The wall is asbestos sheeting with a 1.2m gas hotwater service sitting in front of it.
The plan is to rip as much of the asbestos sheet off the wall above the heater as possible to access the comb. I was told they have only been there for about a year, so hopefully they do not have too much comb in there.