In a bowl whisk together vinegar, soy sauce, mirin, sesame oil, garlic and ginger.  Place chicken in a non reactive dish and pour over marinade.  Place in fridge for an hour occasionally spooning the marinade over the chicken.  After an hour take chicken out of fridge and place on bench for 30 minutes before cooking.

Pre heat oven to 180°C.

Heat the oil in a large flameproof roasting pan over medium-high heat.  Add chicken, breast-side down. Cook for 5 mins, turn and cook for a further 5 mins.  Add lemon slices to pan and place in oven to roast for 40 minutes or until juices run clear.

In a small saucepan add the lemon sauce ingredients over medium-low heat.  Bring to the boil and allow to simmer for 2 minutes to thicken.

Allow chicken to rest out of the oven for 10 minutes, then pour over the sauce and serve.