Dull light and through double glazing but recognisably a green sand on our garden pond.
Our plot of damp woodland and small well vegetated ponds resembles its breeding habitat...(if only!) tho' 15 degrees too far south.
Green sands have been visiting us in winter for some years and when I first excitedly informed Hywel, he of course knew that plus all the other small local sites where they are seen,tribute to his immense local knowledge.