Put the lemon juice, honey and five-spice powder in a shallow dish large enough to hold the chicken breasts in a single layer, and mix together until well blended. Make three deep slashes in each chicken breast, then put into the dish. Rub the marinade all over the chicken, and well into the slashes. Cover with plastic wrap and marinate in the refrigerator for at least 30 minutes.
To make the dressing, blend together the yogurt, lemon rind and juice and the parsley and season to taste. Cover and chill until required.
Remove the chicken from the refrigerator to bring to room temperature. Preheat the grill to medium and line the grill tray with foil. Set the shelf on the lowest position. Put the chicken breasts on the tray and cook for about 20 minutes, basting occasionally with the marinade and turning halfway through cooking. Thinly slice the chicken on the diagonal and set aside to cool.
Sprinkle the pita breads with a little water and warm under the grill for 2–3 minutes. Meanwhile, toss the lettuce, tomatoes and carrot with the dressing. Slice open one side of each pita bread to make a pocket. Divide the chicken and salad among the pitas and serve immediately.