Spray a frying pan with low-calorie cooking spray and set on a medium heat. Add the onion, spring onion, garlic and bacon and fry for 5 minutes until softening and turning brown.
Add the courgette, carrots and peppers and continue to fry for 5 minutes.
Add the stock cubes to the water and mix to dissolve. Pour into the pan along with the chopped tomatoes, passata, tomato purée, Cajun-style seasoning, Worcestershire sauce, white wine vinegar and bay leaf. Stir well.
Bring to the boil, then transfer the contents of the pan to a slow cooker and cook for 3 hours.
After 3 hours add the kidney beans, chickpeas and sausage. Season to taste with black pepper.
Cook for another hour. Remove the bay leaf and stir the spinach through until wilted.