Wipe the oxtails dry with a paper towel.
Put the seasoned flour in a resealable plastic bag, then add the oxtail and shake to coat with flour.
Heat the butter and olive oil in the cast iron and sauté bacon pieces over medium high heat.
Remove bacon, add the oxtail to the cast iron and brown in bacon fat. When the piece is browned all over, remove and drain on paper towels keeping warm.
Place the KUDU potjie or dutch oven over the fire, then add 4 finely diced carrots to the pot together with the chopped onions and the leeks and sauté until softened.
Add the oxtail and bacon to the potjie and add the bay leaf, peppercorns, garlic, tomato sauce, beef stock and red wine.
Bring slowly to a boil. Cover tightly with a lid and allow to cook undisturbed for 4 hours.
One hour before serving, add the remaining carrots and mushrooms without stirring.
Remove and serve over rice or polenta.