Preheat the oven to 180°C/350°F/ Gas Mark 4, 10 minutes before roasting. Weight the joint and calculate the cooking time at 20 minutes per kg + 70 minutes at the end. Wipe the turkey joint and reserve. Warm the redcurrant jelly until smooth and brush 1-2 tbsp over the turkey.
Heat the oil in a pan and gently sauté the onion and garlic for 3 minutes. Add the mushrooms and continue to cook for further 2 minutes. Add seasoning to taste and the chopped parsley and arrange on top of the turkey.
Arrange the streaky bacon across the mushroom topping so that the mushrooms are completely encased. Place in a roasting tin and cook in the oven for the calculated cooking time. Remove from the oven and leave to rest for 10-15 minutes.
When ready to serve, warm the remaining redcurrant jelly and pour over the joint, garnish and serve with freshly cooked vegetables and a gravy of your choice.