Heat the oven to 180c/fan 160c/gas 4. In a large casserole pan, bring the chicken stock and white wine up to the boil. Put the chicken into the pot and put the lid on. Put the pot into the oven and cook for 1½ hours or until the chicken is cooked (check by piercing the thickest part of the thigh – the juices should run clear). Remove the chicken from the pan and keep warm. Put the pan back on the hob, add the diced bacon and reduce the cooking liquor down over a high heat by about ½ until it reaches a thicker sauce-like consistency. Gently stir in the butter until the sauce goes glossy. Add the peas and heat through. Finally, stir in the lettuce and mint and wilt down a little. Blowtorch the chicken or slide it under a hot grill to give the skin a litle colour and serve with the peas and gravy.