Preheat the oven to 220°C. Rub sea salt all over the chicken. Sprinkle freshly crushed black peppercorns. Put 3 lemon halves into the chicken cavity. Tie up the 2 legs together with a string. Sprinkle grated lemon rind over the chicken.
Halve 3 each of small red and yellow capsicums and put into a baking dish. Add 1 quartered onion, 4 garlic cloves and place the chicken over them. Drizzle around 4 tbsps oil over the chicken.
Squeeze the juice of ½ lemon and keep the dish in the preheated oven and cook for 15 minutes. Reduce temperature to 170°C and cook for 1 hour. Heat 2 tbsps oil in a non stick grill pan. Put 5 garlic cloves, 1 quartered onion on the grill pan.
Slice ½ green zucchini into round slices and place on the pan. Similarly slice ½ yellow zucchini into round slices and place in the pan. Place thick slices of green capsicum on the pan too. Halve 2 each small red and yellow capsicums and put into the pan.
Chop a little curly parsley. Let the vegetable in the grill pan cook till grill marks appear on them. Sprinkle salt and pepper powder over them. Bring the chicken out of the oven, drizzle remaining oil over it and put it back in the oven till the chicken is completely done.
Remove the lemon halves from the chicken cavity.
Arrange the grilled vegetables on either sides of a serving plate. Sprinkle parsley over the vegetables. Keep the chicken between the vegetables and serve hot.