I'm relieved to say that Hedgie is not trapped in the compost bin. I went out with the torch one dark night - hedgehogs are nocturnal - to discover her gone.
Had she been coming and going freely all along? Or had my intrusion with the camera driven her away?
I fretted. I checked the bin over and over. I felt responsible for her departure. Then, two days later she was back - snuggled under some spinach leaves.
I still can't see how she gets in and out but she does.
I was reminded of this New Zealand cartoon strip by Burton Silver, first published in the 1970s about a woodsman called Bogor who befriends a nameless hedgehog.
It's nice to know a hedgehog has taken up residence in the garden. And it would be amazing to be like Bogor and keep her as an almost-pet. But she's best left alone.