A bit of 'closure' and some happy stories tonight.
We finally buried BLB under some of our Lavender - it seemed a fitting end for him and he'll continue to be part of the bee community in his own small way. We took photos of him today so that we could finally try and identify his gender - and finally we could confirm that he was a boy.
Amongst other things, one way to tell is from the segments on the antennae - from the joint to the front tip boys have 10 segments and girls have 9. Yet another amazing fact of nature that would've have ordinarily have gone unnoticed to this casual observer! Here's a close-up of his antenna (it also shows the long tongue and sheath):
He created a lot of laughter for us while we had him, not mention a lot of curiousity about his behaviour. RIP BLB!