Fry the onions, garlic and green pepper in a pan until soft, then add the minced beef and fry until lightly browned.
Blend together the chilli powder, flour, brown sugar, cumin, oregano, paprika and tomato puree to make a paste. Stir the paste, canned and fresh tomatoes, thyme and seasoning into the pan. Add the bay leaf too.
Put all of the ingredients into the slow cooker and cook for 3 - 7 hours dependant on heat setting. One hour before serving add the kidney beans.
Check the seasoning, add a touch more salt & pepper if required.
Just before serving, mix the chopped chives into the soured cream to serve with the chilli.