Preheat oven to 180ºC / 350°F / Gas Mark 4. Score the chicken fillets with a sharp knife, season with salt and pepper. Place in a shallow roasting tray and roast for 30 minutes then drain off the cooking juices. Mix together the lemon juice, honey and mustard and drizzle over the chicken and roast for a further 15 minutes until sticky, basting once or twice. Ensure chicken is cooked through. Meanwhile boil the potatoes and cook until tender, then drain. Boil the cabbage for 4-5 minutes until tender, then drain. Pour the milk into a large pan and simmer. Add the spring onions and cook for 2-3 minutes until soft then add the olive oil. Add the potatoes to the pan and mash. Season and stir in the cabbage. Serve with the chicken and juices from the roasting tin.