Preheat the oven to 210C/200C Fan/Gas 6-7.
For the spelt mixture, heat the oil in a large saucepan over a medium-low heat. Add the onion and garlic and fry gently for about 10 minutes until soft. Add the spelt or barley and stir well.
Pour in 450ml/16fl oz stock and bring to the boil. Reduce the heat and simmer, uncovered, until the grain is tender and most of the liquid has been absorbed: about 20 minutes for spelt, a bit more for barley. Top up with a little more stock or boiling water if needed.
Remove from the heat and stir in the chopped dried apples, lemon zest and juice, and plenty of salt and pepper. Set aside in the warm pan.
While the spelt is cooking, untruss the chicken and put it in a roasting dish. Smear it all over with the rapeseed oil and season the skin and cavity with salt and pepper. Put the bay leaves and one sprig of thyme in the cavity. Tuck the remaining thyme underneath the chicken.
Roast the chicken in the hot oven on its side for 10 minutes. Remove and turn the chicken onto its other side for a further 10 minutes. Baste the chicken with its own juices and roast breast-side down for a further 20 minutes.
Remove the chicken from the oven, turn upright and spoon some of the spelt mixture inside the cavity. The cavity should be no more than two-thirds full as the stuffing will expand in the oven. Put the remaining spelt in the tin around the bird. Trickle 125ml/4fl oz of hot stock over the spelt.
Turn the oven setting down to 180C/170C Fan/Gas 4. Return the tin to the oven and roast for a further 30 minutes, or until the skin is golden-brown and crisp. To check the bird is cooked, pull at one leg. It should come away from the body with relative ease and the juices between the leg and breast should be clear. If the juices are a bit pink and the leg a bit reluctant, then return to the oven for a further 10 minutes and test again.
While the chicken is cooking, place the kale in a steamer and cook for 4 minutes, or until tender but not too soft. Melt a knob of butter in a large frying pan and add the chopped leeks, gently fry for 15-20 minutes or until soft.
Carve the meat and serve with spoonfuls of the spelt mixture, kale and leeks.