Is it worth perhaps putting some of the compost into a pot as Simmo says, and carefully moving the brood (cells) into it? The bees will Know the scent of their brood, and will hopefully follow it. They may re-establish a small nest before winter so that the normal life-cycle can resume. My neighbour recently destroyed a BB nest when cutting his side of the hedge, and panicked. I gathered what I could and put it in my raspberry cage on the other side of the hedge, in a similar habitat a few feet away, and nowtake great pleasure in the bees checking me out and buzzing around my head when I go in to pick. I watched them excavating the site of their new nest (fascinating!), and I really think they have helped my rasps with pollination. They also attack any wasps that come too close, so they have been less of a prob in there this yr. I have a nest of BB under my shed every yr, although the exact site and entrances change. I believe that they never use the same site twice, but will stay nearby if undisturbed. Incidentally, my wee boys are happy to rescue any BB we find in the conservatory by feeding them with jam, honey or sim, on their fingers, and have never been stung. They are lovely creatures! Save if you can, pls.