I disagree with Peter. By that argument Scotch Eggs shouldn't exist in shops. It's a snack you buy at a shop and eat on the train or whatever. Just like a sandwich. Or a pork pie. Or a scotch egg.
I don't care what Peter does.. no one thinks "I'm off on a train journey today. I best cook some boiled eggs to take with me." but I bet plenty of people will think "Ohh boiled eggs" when in WH Smith or whatever shop is at the station.