Heat a splash of oil in a large frying pan and season the pork. Brown in two batches for 10 mins each, transferring the meat to a medium casserole dish. Add 100ml cider to the frying pan and let it bubble and reduce. Scrape up any bits from the bottom of the pan and tip the liquid over the meat.
Wipe out the pan. Heat 1 tbsp oil and add the bacon, onions, carrots, bay leaves, 2 thyme sprigs and some seasoning. Fry for 10 mins over a high heat, stirring often, until golden.
Meanwhile, half-fill a large bowl with cold water and add the lemon juice. Scrub the artichokes then slice thinly lengthways, leaving the skin on, and drop into the water. Heat oven to 160C/140C fan/gas 3.
Stir the flour into the vegetables and bacon, cook for 1 min, then stir in the stock and remaining cider. Season, bring to a simmer, then stir into the casserole. Drain the artichokes and pat dry, then use to cover the stew in two layers, overlapping the slices generously. Season, brush over a little butter, and sprinkle over the leaves from the remaining thyme sprig. Bake, covered, for 1 1/2 hrs, then uncover and cook for a further 30 mins. To crisp the top, brush again with butter, heat the grill to high and grill for 5 mins. Leave to stand for 5 mins before serving.