Spray a flame-proof casserole dish with the cooking spray and fry the veg over a medium heat for about 10 minutes, until softened.
Add the wine and let bubble, then add the stock and bring to a simmer.
Meanwhile wash the lentils in cold water, then cover in a pan with cold water. Bring to the boil, cover, and simmer for 20 minutes.
Spray a frying pan with cooking spray and fry the sausages until browned.
Drain the lentils and add to the vegetable mixture with the sausages and tomatoes.
Bring to the boil, and cook in the oven at 150°C for 1 hour and 40 minutes, stirring occasionally, and adding water if the lentils look dry.
Alternatively, once bubbling transfer to a slow cooker and cook on medium for around 5-6 hours.