For the sauce, fry onion, garlic, celery in oil until soft, add peppers, bay leaf, herbs and tins of tomatoes, basil. Simmer away. Adjust this if you wish, it's just a guide for a basic sauce
Peel sausage meat from skin and put in a bowl, mix in breadcrumbs, diced onion and garlic and tomato purée and mix. Add herbs, you can play around with this.
You have to stuff your tubes with the mixture which can be messy, it's best done with your fingers. Have a baking tray ready and pour a layer of your sauce in to cover the bottom so the tubes dont stick. place the tubes in a SINGLE layer - don't put them on top of each other, it doesn't work. Squeeze as many in as you can. Cover with your sauce.
Put in to a pre-heated oven at 200 degrees Celsius for an hour. I would normally throw a tiny bit of cheese on in the last few mins (not at the start sometimes it burns the top).
You will notice the sauce thickens right up and it looks like a lasagne. It's very rich with all the red sauce so small portions would work well.