I eventually caught it gone 3am after it got tired and holed out on the lintel for the bathroom door. Wrapped it gently in a towel and popped it back out through the landing window.
They are insanely cute close up, and so delicate. And it was buzzing while I held it, so I imagine that was its sonar in overdrive, probably swearing some at the annoying klutzy human.
Lexi was kept entertained pogoing after it, but she couldn't jump high enough / fast enough. If that had been Madam Poppy, she'd have caught it, as she was the expurrt in catching dragonflies in mid air.