Nick W:

You asked for "ideas" ??

Somed years ago a homeowner asked me to eradicate bees from an outbuilding.  Not
knowing what was there, I suited up and went inside.  For once it was SO easy.
Bumblebees had nested in a small hand pushed floor cleaner.  I asked for a pan
of water (preferably hot) large enough to accommodate the cleaner, and plunged
the whole thing in at once.   Easy, safe, effective, cheap etc  <vbg>

So..............maybe  it would be possible to be inventive and remove bees
from    the colony with a power vaccuum cleaner, vented into a tank of water?
(Some models are built with a water container, instead of using disposable dust
bag).

All the best,

Eunice