Place the lamb in a large non-metallic dish. Place all the remaining ingredients in a food processor and blend until smooth. Season well and pour over the lamb. Cover and marinate in the refrigerator for 24–48 hours.
Remove the lamb from the refrigerator, and allow to come to room temperature. Preheat the oven to 200°C (400°F), Gas Mark 6.
Thread the lamb on to 8–12 metal skewers, and arrange on a baking sheet lined with greaseproof paper. Cook in the preheated oven for 12–15 minutes until tender and cooked through.