Preheat the slow cooker if necessary; see the manufacturer's instructions. Heat the oil in a large frying pan, add the chicken and onion and fry, stirring, until lightly browned.
Stir in the garlic and flour, then gradually mix in the stock. Add the red pepper, sweetcorn, haricot beans and new potatoes. Add the thyme and a little salt and pepper and bring to the boil, stirring.
Transfer the mixture to the slow cooker pot and press the chicken and potatoes below the surface of the liquid. Cover with the lid and cook on low for 8–9 hours or until the chicken is cooked through and the potatoes are tender.
Stir well, then spoon into shallow bowls and sprinkle with a few extra thyme leaves, if liked. Serve with hot garlic bread.