Heat oil in a casserole over medium-high heat. Dust lamb neck with seasoned flour, shaking off excess, add to casserole and turn occasionally until golden (3-5 minutes), remove. Add onion and garlic, stir occasionally until just tender (5-10 minutes). Deglaze casserole with wine and cook until reduced by half (5-10 minutes), then add stock, return lamb to pan, reduce heat to low and cook, covered, until lamb is just tender (2 hours).
Meanwhile, trim tops of artichokes by 2cm with a serrated knife, remove outer leaves with your fingers until you reach the pale inner heart (discard leaves). Trim stems to 5cm, peel green exterior until you reach pale inner flesh. Peel outside of stem with a vegetable peeler to smooth, remove remaining green fibres, then remove inner hairy choke from heart with a melon-baller. Halve artichokes lengthways, place in a bowl of acidulated water until required.
Drain artichoke well, add to lamb and cook for 15 minutes, then add broad beans and peas. Cook until artichoke, beans and peas are tender and lamb is very tender (15 minutes), season to taste and serve.