Very at the scamorza - never seen it ouside London. And not out in the sticks... But then I like my scamorza melted with wine and served with good bread.
But for me a ragu needs to start with onion, celery, carrot and good olive oil. Then add good quality pancetta cubes, followed by mince. Tinned toms, tom puree, mixed herbs (fresh if possible but dried oregano) and a good pinch of sugar. I sometimes use some good quality veg stock as well. Cook in pressure cooker and the family recipe also has a good slug of milk added at the end, although I do not always do this.
And then layer with bechamel and lasagna sheets - bechamel, pasta, ragu, bechamel, pasta, for a couple of layers - and top with bechamel and cheese. Mozzarella and parmigian as a minimum.
I made a big lasagna on Saturday afternoon - it was fab!