Season the lamb with sea salt and freshly ground black pepper and dust with some of the flour. Add the oil to a large pan and brown the lamb in batches, keeping the neck fillet pieces separate from the cutlets. Remove from the pan.
Melt the butter in the pan and sweat the onions until translucent. Add the pearl barley and mix well to cover the grains in butter. Season and sprinkle with a little flour and stir well.
Pour in the Essential Cuisine Lamb Stock and Worcestershire sauce and add the thyme. Bring to the boil and remove from the heat. Season with salt and pepper if needed.
Mix the onion and barley mixture with the nect fillet pieces and divide between 4 individual hotpot dishes. Arrange 2 cutlets vertically in the centre of each hotpot, with the bones upright.
Arrange the potato slices in an overlapping pattern on top of the meat, so that the bones protrude from the potatoes. Brush the potatoes with the melted butter, then season with salt and pepper. Cover with aluminium foil and place in the oven for 1 hr 30 mins at 140'c.
Mix the breadcrumbs, mint and vegetable oil together. Remove the foil from the hotpots and turn the oven up to 200'c.
Sprinkle the breadcrumbs evenly over the potatoes and cook for a further 20-30 minutes until the potatoes and breadcrumbs are golden brown and crisp.
To make the spiced cabbage and beetroot, put the two vinegars into a pan along with the sugar and spices. Bring to the boil and reduce by half, then pass through a fine sieve.
Melt the butter in a large pan and add the cabbage. Sweat over a low heat until soft, then add the beetroot and mix in the vinegar reduction. Warm through before serving alongside the hotpots.