Heat the olive oil in a large oven proof pan on medium heat and cook the bacon for 5 to 6 minutes until crisp. Once the bacon is cooked, remove it from the pan and set aside on a paper towel, leaving the grease in the pan.
Sprinkle the chicken with salt and pepper and place the pieces skin side down in the pan. Sear for approximately 6 minutes until the skin is golden and crisp and then flip and cook for another 5 minutes. Once the chicken is cooked through, remove it from the pan and set aside on a plate.
Add the mushrooms, carrots, onions and celery to the pan, sprinkle with salt and cook for 5 minutes until the onions become translucent. Stir in the garlic, thyme, bay leaves, cooked bacon, tomato paste, beef stock and red wine vinegar and increase the heat to high so that the liquid is simmering. Leave it to cook for 8-10 minutes until the sauce has reduced by 1/4.
Return the chicken to the pan and place it in the oven to bake for 20-25 minutes until the chicken is cooked through. Once done cooking sprinkle with fresh chopped parsley and serve with cauliflower mash.