Preheat the oven to 190C/Gas 5.
1) Cut the tomatoes lengthwise into quarters and remove the seeds. Trim the courgette and cut it in half crosswise and then cut each piece in half lengthwise once if the piece is thin and twice if it is thicker, so that the pieces are relatively uniform.
2) Remove the outermost layer of the fennel bulb and discard. Cut the bulb in half so that each half retains part of the stem end. Cut each half into 8 thin wedges so each wedge is held together by a little piece of stem.
3) Put the vegetables into a large baking tin. Toss them with 2 tablespoons oil and 1/4 teaspoon of salt. Arrange the chicken pieces in the pan with the vegetables.
4) In a small bowl combine 1 tablespoon of oil, 1/2 teaspoon of salt, the garlic, lemon zest and lemon juice. Rub the mixture into the chicken in the pan. Season with a few turns of pepper.
5) Roast in the oven for 30 minutes, then give the vegetables a stir and add the rosemary. Cook for about 20 to 30 minutes more until the chicken is done and the vegetable are tender and beginning to brown.