Scottish, Irish and English bacon are pretty much the same from what I can see. The cheap stuff from the supermarket will shrivel up to nothing when cooked, good quality bacon will not.

Sometimes in Scotland you get Lorne sausage, which is square, flat and skinless.

Here in Norn Iron a farl tends to be called a "soda", not to be confused with soda bread. I have no textbook definition of an Ulster fry, but the essentials would seem to be bacon, sausage, potato bread, toast and fried egg. Black pudding, tomato, mushrooms, baked beans and even hash browns are sometime included. In the Republic, soda bread is more common and also white pudding is popular, although goodness knows why since it is horrible!