Ireland was very much an agrarian place at the time, with very little manufacturing or heavy industry. I'm not at all sure there would have been support for industrial-scale canning.
Both of which are in the middle of England which would have involved shipping shellfish to England before the invention of refrigeration. Oceanic travel on the fastest steam powered passenger vessels of the time maxed out at 13 knots or approximately 15 mph. Cargo ships are going to be slower many will be using sail so closer to 6 knots. Dublin to to Liverpool is about 191 miles by sea. So 31 hours away just counting transit how long are these warm clams good for?
Was it warm in the North Atlantic in the 1840s winters? Shellfish will keep for a few days to a week at refrigeration temperatures, 31 hours seems feasible at least several months a year in this hypothetical scenario.
