Start this recipe by marinating the chicken pieces. Mix all of the ingredients together to form the marinate then toss in the chicken and coat all over. Allow to marinate for at least 12-24 hours. When you are ready to cook, thread the marinated chicken pieces onto the soaked wooden skewers. Heat a little oil in a griddle pan and cook the skewers for 10-15 minutes, basting with a little melted butter during the cooking time. Meanwhile, to make the raita, half the cucumber, de-seed and grate. Mix in a good pinch of salt and place into a sieve. Allow to drain for 10 minutes then squeeze out any excess water. Next, place into a bowl with the Greek yogurt, sliced onion, lime juice, spices and fresh mint and mix together. To serve, place the raita into a bowl and place onto a large slate serving plate along with the warmed naan bread. Place on the cooked tandoori skewers and sprinkle over come fresh coriander leaves