Soak the wooden skewers in cold water for 20 minutes, this will help to stop them burning under the grill.
In a mixing bowl, add 100g of the yoghurt along with 2 tsp of the mint sauce, cumin, salt and pepper. Mix well.
Add the diced lamb and mix well. Cover and place in the fridge for 20 minutes to marinate.
Thread 4 pieces of the lamb onto the skewers, alternating with a piece of green pepper and onion. Repeat until you have filled all 8 skewers.
Place the skewers onto a baking tray and cook under a grill for 10 minutes, turning over halfway to ensure even cooking.
While the lamb is cooking, mix 2 tsp of the mint sauce with the remainder of the Greek yoghurt.
Serve the kebabs garnished with the mint yoghurt, lemon wedges and fresh mint.