Wash and roughly chop the vegetables, without peeling them; break the garlic bulb into cloves, leaving them unpeeled. Place all the vegetables and garlic into the middle of a roasting tray and drizzle with 2 tabelspoons of olive oil.
Drizzle the chicken with the remaining olive oil and season with salt and pepper, rubbing it all over the bird.
Carefully prick the lemon all over, using the tip of a sharp knife. Put the lemon inside the chicken's cavity, with the bunch of herbs.
Place the chicken on top of the vegetables in the roasting tray and put it into the preheated (240°C) oven. Turn the heat down immediately to 200°C and cook the chicken for 1 hour and 20 minutes
Baste the chicken halfway through cooking and if the vegetables seem dry, add a splash of water to the tray to prevent burning.
When cooked, take the tray out of the oven and transfer the chicken to a board to rest for 15 minutes. Cover it with a layer of tinfoil and a tea towel and put aside.
Take out the lemon and herbs from the chicken's cavity, carve and serve with roasted vegetables.