Preheat the oven to 180°C (gas mark 4).
In a large oven-proof pan, heat 30ml of oil over medium heat. Season the meat with the herbs, salt, and pepper, and sear on all sides until browned. Place the pan in the oven and roast the meat for 20 minutes or to the desired degree of doneness; remove from the oven and allow to cool. Slice into thin slices and set aside.
Meanwhile, place the courgette slices and tomato wedges on a baking sheet. Drizzle with the remaining olive oil, season with salt and pepper, and place in the oven at the same time as the meat for 20 to 30 minutes or until well-roasted. Set aside.
Place a tortilla on a flat surface, spread with mayonnaise, and top with the avocado, lettuce, meat slices, and roasted vegetables. Roll up and then wrap in parchment paper. Cut in half and serve.