Toss the lamb with the rosemary, garlic, oil, and the vinegar and let marinate in the refrigerator for 1 hour.
While the lamb is marinating, blanch the potatoes and carrots. In well-salted boiling water cook the potatoes for 5 or 6 minutes then transfer with a skimmer to a platter or sheet tray. Cook the carrots for 2 or 3 minutes and reserve with the potatoes.
Heat the olive oil in a large saute pan on medium-high heat until the oil begins to smoke. While the oil is heating, remove the lamb from the marinade and season with salt and pepper. Sprinkle the lamb with the flour and toss to coat. Shake excess flour from the meat and add half to the pan in a single layer so as to sear the meat on all sides, about 2 minutes on each side. Remove to a plate. Repeat with remaining lamb.
Carefully place the potatoes and carrots in the pan used for the lamb. (The olive oil will have lots of flavor from the lamb.) Season with salt and pepper and saute until lightly caramelized, about 4 minutes. Stir from time to time and regulate the heat so the vegetables do not caramelize too much on one side. Transfer to a platter or large plate so that they can be spread out in a single layer.
Pour off and discard the residual oil in the pan. With the pan still on medium heat, deglaze with the wine and reduce by half then add the stock. Bring to a simmer and reduce again by half. Add the seared lamb to the pan and gently toss to incorporate with the pan sauce. Adjust seasoning with salt and pepper, to taste.
In a Dutch oven or large, deep baking dish, add the lamb, wine and broth mixture and rosemary. Cover then place in the pre-heated oven for 45 minutes.
Add the potatoes, carrots and spring onions to the stew. Mix carefully to incorporate. Add a little stock or water, if necessary, to keep the stew moistened. Continue to cook in the oven, covered, until the meat and vegetables are tender, about 10 more minutes.
Stir in the parsley and lemon zest. Taste and add salt and fresh ground pepper if needed. Serve directly from the baking dish.