Put the skewers in a bowl of water to soak.Tip half the yogurt into a large bowl. Add 1 tsp harissa. Zest the lemon and set aside. Squeeze the juice from half the lemon into the yogurt. Peel and grate in a garlic clove. Add ½ tbsp olive oil and a large pinch of salt and pepper. Cut the lamb into 2cm pieces. Add to the bowl and mix. Set aside to marinate.
Halve the onion and peel it. Finely dice one half. Peel and grate the remaining garlic. Add them to a pan. Tip in the bulgar wheat. Pour over 200ml boiling water and set on a gentle heat to simmer. Cook for 10-15 mins till the bulgar is tender and the water has been absorbed. Leave to cool.
Heat the grill to its highest setting. Cut 2 tomatoes into 4 thick slices each. Place on a tray lined with foil. Thickly slice the remaining onion half. Thread the lamb onto the skewers, adding a couple of pieces of onion per skewer. Place the kebabs on the tray with the tomato slices. Cut the lemon half into 4 wedges and add those too.
Slide the kebabs under the grill. Cook for 10 mins, turning the kebabs once. The should be slightly charred in places and cooked through. The tomatoes and lemons should be softened and slightly blackened.
While the kebabs are cooking, finely dice the remaining tomatoes. Roughly chop the rocket. Add to the pan with the bulgar. Add the lemon zest. Season and stir together.
Heat a large frying pan or wok. When warm, drizzle in 1 tbsp olive oil. Add the sweet bite peppers to the pan and cook for 2-3 mins, turning now and then till a little blackened and wrinkled. Scatter with sea salt. Roughly chop the mint leaves.
Divide the bulgar tabbouleh between two plates. Top with the kebabs, tomatoes and lemon wedges. Drizzle over any of the cooking juices. Spoon on a dollop of the remaining yogurt, a scattering of mint and a sprinkle of harissa to taste. Serve with the sweet bite peppers.