Make the tzatziki. Mix together the yogurt, crushed garlic, cucumber and chopped parsley, transfer to a small bowl and set aside.
Put the lamb, cumin, ground and fresh coriander, garlic and onion in a food processor and blend until well combined but still retaining a little texture.
Divide the mixture into 4 and use damp hands to shape it around 4 metal or presoaked bamboo skewers. Cook under a preheated hot grill for 3–4 minutes, turning regularly until browned and the lamb is just cooked through.
Serve 2 kebabs in a toasted pitta bread with crisp green salad and a spoonful of tzatziki.