Preheat the oven to 160C/325F/Gas 3. For the chicken casserole, place the chicken into a large ovenproof pan or casserole. Add the carrot, celery, peppercorns, herbs, stock and white wine and bring to the boil. Season, to taste, with salt and freshly ground black pepper.
Cover with a lid and place into the oven to cook for 1½-2 hours, or until the chicken is completely cooked. You can test if the chicken is ready by gently pulling the leg away from the carcass - it should come away easily and the juices should run clear when pierced with a skewer or sharp knife. (For a larger chicken, cook for 20 minutes per 450g/1lb, plus 30 minutes extra.)
Remove the chicken from the stock (reserving the stock) and place it onto a large plate. Remove all the meat from the carcass, discarding the skin and bones.
Cut the chicken meat into strips approximately 1cm/½in wide and 5cm/2in long. Cover and keep warm.
Strain the stock into a clean pan and discard the vegetables, peppercorns and herbs. Add the lactose free cream to the pan, bring up to the boil and boil, uncovered, for a few minutes. If the flavour is a little weak, boil for longer until reduced slightly. Season, to taste, with salt and freshly ground black pepper.
Meanwhile, heat a saucepan over a medium heat and place the butter into the pan. When the lactose free butter has melted, add the flour, stirring continuously. Cook over a low heat for two minutes to form a roux.
While the lactose free cream sauce is still boiling, gradually whisk in the roux - you need enough to thicken it so that it just coats the back of a spoon. Place the chicken and any juices back into the pan and season, to taste, with salt and freshly ground black pepper.
Meanwhile, for the pilaff, heat the lactose free butter in a saucepan large enough to contain all of the rice. Add the rice and stir for about two minutes.
Add the stock and season, to taste, with salt and freshly ground black pepper. Bring to the boil, then turn the heat right down and simmer gently for about ten minutes, or until the rice is just cooked and all the liquid is absorbed.
To serve, pile the rice onto serving plates and spoon the chicken casserole over the rice.