Grasscarp: I used to have to travel to Belgium on a regular basis many years ago and saw this on a restaurant menu, I didn't have the faintest idea what it was but thought i'd have a go anyway, imagine my suprise when I found that I had ordered a bowl of whelks!!
I can get cockles from the local market fishmonger ..along with some fresh chips from the stall opposite that must be my favourite food .
You used to be able to get tripe too.... wesand and jot mixed ,that with chips( cooked in beef dripping ) and plenty of salt and vinegar ..mmmmm.