Confidence: I'm as sure as I can be.
Notes: Identity confirmed by Peter Morden NHM-Mollusca - many thanks! E. vermiculata is an alien originating in S. Europe, and is a pest in some parts of the world having been introduced through the food trade. As a non-native it is an offence to release this species in the UK.
Published as: Notton, D., 2006. Eobania vermiculata in the UK. Mollusc World, No. 11: 6.