Heat a little oil in the casserole dish and brown the sausages all over. Then using a slotted spoon, remove them to a plate. Add the bacon and onions to the casserole and brown lightly, sprinkle in the flour to soak up the juices and gradually stir in the wine.
Pop the sausages back in with the garlic, bay leaf, thyme and a little seasoning. Put the lid on and simmer on the hob very gently for 30 minutes.
Next add the mushrooms, stirring them in and cook for a further 20 minutes without the lid this time.