Grubs in my compost

I've long found these large grubs in my compost. I figure they're part of the regular compost ecosystem and I throw them back in when I fork them out along with the compost. Does anyone know what they are? I have my suspicions and I'll Google a bit and post what I find later this week if I get around to it.



That's a quarter next to it for scale. He's playing possum on his side with his mouth end at the left.


Update 17 December: I believe that the grubs I found in my compost are Cotinus mutabilis aka Green Fruit Beetle, Green Fig Beetle, June Beetle . These are the striking and large metallic green beetles that hover through the garden in summer.