Place the sausages in the heavy-bottomed frying pan over a low heat. Slowly start to cook the sausages. As the fat starts to render you can turn up the heat.
Fry the sausages turning regularly until brown then carefully remove from the pan.
Add the onion, carrot, and celery to the pan and saute until golden brown and cooked through.
Add the garlic and cook out for a couple of minutes stirring contiously.
Add all of the remaining ingredients and bring to a gently simmer, covering with the lid. Stir occassionally to prevent the casserole sticking and burning.
After fifteen minutes add the sauages and cook for another fifteen minutes.