Heat the canola oil in a medium (10- to 11-inch) ovenproof pot or Dutch oven, such as Le Creuset, over medium heat. Add the bacon and cook for 5 minutes, until browned. Transfer the bacon to a large plate, leaving the fat in the pan. Dry the lamb with paper towels and toss it in a bowl first with 1 tablespoon salt and 1 teaspoon pepper and then with the 1/4 cup of flour. Raise the heat to medium high and cook half the lamb in the bacon fat for 5 minutes, turning occasionally, until browned. Add the lamb to the plate with the bacon and brown the second batch, also transferring it to the plate. Add the garlic to the pot and cook for one minute.
Pour the lamb and bacon, along with any juices that collect, back into the pot. Add the beef stock, wine, tomatoes (including the juice), thyme, rosemary, 2 teaspoons salt and 1 teaspoon pepper and bring to a boil, scraping up the brown bits in the pot. Simmer for 5 minutes, cover and place in the oven for 30 minutes. Add the carrots, potatoes, onions and turnips, cover and return to the oven for 1 hour, until all the vegetables are tender.
Mash the 2 tablespoons of flour with the butter in a small bowl. Stir the mixture into the stew and simmer on top of the stove for 3 minutes. Off the heat, stir in the peas and parsley, season to taste and serve hot in large shallow bowls.
To peel the onions, drop them in a pot of boiling water for 30 seconds, then trim and peel them, leaving the root intact.