The Hairy Bikers recommend perparing the chicken the day before cooking.
1. Remove the chicken from its packaging. Sprinkle the cavity with a little sea salt, then place the chicken on a plate. Sprinkle the skin of the chicken with more salt, then cover loosely with kitchen paper and leave it in the fridge. Remove the chicken from the fridge an hour before you want to cook it, so it can come up to room temperature.
2. To make the stuffing, heat the butter in a frying pan. Add the onion and celery and cook until soft and translucent. Add the garlic and continue to cook for another two minutes. Pour everything into a bowl and leave to cool. Then add the remaining stuffing ingredients and season with salt and pepper. Mix thoroughly, then spoon the stuffing into the cavity of the chicken. Preheat the oven to 220°C/Fan 200°C/Gas mark seven.