Humble chicken stew & dumplings

Name: Humble chicken stew & dumplings
Cook time: 1 h 40 min
Total time: 1 h 40 min
Cuisine: British
Ingredients: 4 rashers of higher-welfare smoked streaky bacon; olive oil; 2 onions; 3 large carrots; 2 potatoes or 250g celeriac; a few sprigs of fresh thyme; 2 fresh bay leaves; 200 g button mushrooms; 1 heaped tablespoon of plain flour; 250 g self-raising flour; 125 g cold unsalted butter; 1 leftover chicken carcass plus up to 300g leftover cooked chicken