Heat the oil in a large non-stick pan and fry the beef in about three batches until well browned. Set aside.
Add the mushrooms, bay and thyme to the pan, and cook for about 5 mins. Tip in the onions and garlic, and cook for a few minutes more until softened.
Return the beef to the pan and add the carrots, stock and tomato purée. Cover and simmer for 2 hrs until the meat is tender and the liquid has reduced to a thick gravy.
About 25 mins before the end of the cooking time, make the mash. Bring a large pan of water to the boil and add the swede. Boil for 5 mins, then add the potato and boil for 15-20 mins until tender. Drain and mash with plenty of black pepper.
You can eat half the stew and mash now, then chill the rest to reheat and eat another day. Will keep chilled for a few days. Reheat the stew in a pan until piping hot. The mash can be reheated in the microwave. Serve with broccoli or peas, if you like.