Combine flour, salt and pepper in a bowl; add beef, tossing to coat. Shake off any excess flour.
Heat olive oil in a large frying pan over medium-high heat. Add onions and beef, stirring until browned. Pour in beef stock and add bay leaves and curry powder. Stir well, bring to the boil, then reduce heat and simmer for 30 minutes. Stir in carrots, rice vinegar, treacle and potatoes; simmer for an additional hour until beef and vegetables are tender.