Dog whelk population here - live and kicking.
No interactions present.
Graham, I think you ought to tag this Marine but surely it's not Urban in the normal sense?
Your note about names - it is accepted as the Dog whelk, nowhere (I could find) is Dogwhelk used.
Picture 2 then - is that a Native Oyster Ostrea edulis?
THREE MARINE PROJECTS
Lat/Lng: 51.3832, 1.3256
OS grid ref: TR315701