Preheat the oven to 200°C/180°C fan. Remove the chicken jus from the fridge. Peel and roughly chop the onion and carrot. Clean the mushrooms and chop them into quarters. Peel and mince the garlic. Chop the turkey bacon into small pieces. 

Heat a pan over a medium-high heat with a drizzle of oil. Once hot, add the mushroom and turkey bacon pieces and fry for 5 min until crisp. Remove from the pan. Rub the chicken skin with salt, then place it, skin-side down, in the pan. Fry for 5 min until browned. Once browned, transfer to a plate. 

Return the pan to a medium heat with a drizzle of oil. Add the carrot and onion with a pinch of salt and cook for 5-6 min or until softened. Add the garlic, tomato paste and flour. Fry for 1 min further.

Add the chicken jus, water, vinegar, marmite, brown sugar, soy sauce and bay leaves. Bring to a boil, then simmer for 5 min. Transfer to a baking dish or casserole pot. Add the chicken, mushrooms and turkey bacon and bake for 20 min.

Meanwhile, peel and chop the potatoes into bite-size pieces. Add them to a pan of salted boiling water. Cook the potatoes over a medium heat for 15 min or until soft. Once soft, drain the potatoes and return them to the pan with the butter. Mash until smooth and season with salt and pepper, keep warm.

Serve the stew with the mash to the side.