The beetle on the beach didn't look to healthy. I thought is was going to die. Wondering if it had struggled for too long on the warm evening sand, I carried it to the grass near the car park. It started moving then. I don't know whether it was really happier there or perhaps trying to get back to the sand for some more sunbathing.
When I got home I tried identifying the beetle on the beach. Now I was the one struggling. After much deliberation I rejected Chrysomela tremula as its tarsal segments are too long and that type of beetle may now not even exist in the UK. I then thought it may be a Garden Chafer, Phyllopertha horticola, but its head isn't greenish and it doesn't look hairy enough.
I now think it's probably some sort of dung beetle; Aphodius fimetarius. That would explain the ridges in its carapace and the little antennae which are almost invisible on the beach beetle. Did somebody say dung beetle? Yuk, I had that on my hand!