On Quercus, Kingsford Country Park, Worcestershire, 9th October 2021.
Lower image shows larva in opened leaf.
Upper image shows the distinctive signs of habitation with leaf folded and 'tacked' in place with silk.
The dark head and ventral plates are diagnostic features of E. atricollis larvae, the ventral plates being far more obvious in the early/intermediate instars. The image illustrates the same larva and mine photographed a week apart, the image from 23rd Sept. showing the fully mature larva exiting the mine.