Scouse should definitely be made with scrag-end of lamb or mutton. I make it with beef just because I don't much care for lamb, but traditionally, cheap lamb is the correct cut. Basically, people get a bit uptight about what should go in it, when basically it's a dish of leftover veg and cheap meat. There is no correct list of veg to stick in it, but they are usually root veg like spuds, carrots, turnips/swede, onions etc, and a lot of people chuck in celery. I use chunks of meat AND mince, as a bit of mince helps to thicken the gravy. The most important thing is the long cooking time, and serving with large slabs of white bread and pickled red cabbage. Mmmm.