Coat the pieces of beef in the flour. Heat the oil in a casserole pot over a medium/high heat and brown the meat in two batches until browned all over. Remove from the pan, then add the onion and carrot and cook for 6-8 minutes until softened and golden, stirring regularly and scraping the bottom of the pot to release flavour.
Add the mushrooms and cook for 3-4 minutes until softened.
Return the beef to the pot then add the chopped tomatoes, beef stock and bay leaf. Season to taste.
Simmer over a low heat with the lid on for an hour, then remove the lid and simmer for 30 minutes until the beef is tender and the sauce has thickened. Remove from the heat, remove the bay leaf then stir through the horseradish sauce and the parsley.