The main difference between Italian or Italian-American sausages as compared to a British ones is that the meat in Italian sausages is more of a mince and in British sausages it tends to be ground more finely.
Even the sausages I buy at my favourite Italian deli grinds the meat too finely for my taste.
The Sainsbury Sicilian sausage uses more of a mince and would work well in your recipe I think. If you can’t find it, any pork sausage with a thicker mince or even pork mince itself cooked with some herbs, like oregano, fennel, basil, and a splash of wine would make a fine substitute.
She..pie, where are you located?