Preheat your oven to 180°C (350°F, gas mark 4). Begin by draining and rinsing the soaked whole wheat thoroughly. Place it in a medium saucepan filled with plenty of water, bring it to a boil, then reduce to a simmer and cook for about an hour until the grains are tender. Drain and set this aside, ready to be added later. Now season the lamb cubes generously with a teaspoon of salt and freshly ground black pepper. Heat one tablespoon of olive oil in a large, deep sauté pan over medium-high heat. To ensure a beautifully seared crust, add some of the lamb pieces without crowding the pan; cook each side for about four minutes until golden brown. Transfer the browned lamb to a bowl and repeat this process with the remaining lamb, adding extra oil as necessary. Reduce the heat to medium and add another tablespoon of olive oil to the same pan. Toss in the skinned shallots, frying them gently for around four minutes until they are wonderfully caramelized and sweet. Add them to the lamb bowl. Continue with the carrots, turnips, celeriac, and charlotte potatoes, browning each batch with care, and adding more oil as needed to achieve a lovely caramelized finish. These browned vegetables will impart deep flavor to the stew. Deglaze the pan by pouring in the white wine, then sprinkle in the caster sugar along with the fresh thyme and oregano sprigs. Add a teaspoon of salt and a generous grind of black pepper to season. Allow this mixture to boil vigorously for about three minutes, letting the alcohol evaporate and the flavors concentrate. Return the lamb, all the browned vegetables, and the cooked whole wheat to the pot. Pour in the chicken stock, stirring gently to combine. Cover the pot with a lid and bring everything to a boil on the stovetop for five minutes. Transfer the covered pot to the preheated oven and let the stew cook slowly for an hour and a half. This slow cooking melds the flavors and tenderizes the lamb beautifully. When time’s up, carefully remove the stew from the oven. If you notice an excess of liquid, uncover the pot and simmer the stew on high heat for a few minutes to reduce the broth to your preferred consistency. This final step helps concentrate the flavors and thickens the stew slightly. For extra richness, consider adding a pat of butter or a splash of cream before serving. Enjoy your Irish stew warm, sharing its comforting flavors with family or friends.