Heat your oven to 200°C/Fan 180°C/Gas 6. Pour 1 tbsp olive oil into a large ovenproof dish and slide it into the oven to warm up.
Peel the potatoes. Chop them into small, bite-size pieces. Add them to the dish and season with salt and pepper. Turn to coat in the oil and return the dish to the oven. Bake the potatoes for 15 mins.
While the potatoes are cooking, snap the woody ends off the asparagus – bend them and they will break at the right point. Put to one side.
Peel and crush the garlic. Finely grate the zest from the lemon. Mix the garlic and lemon zest together with 1 tsp dried oregano and a pinch of salt and pepper. Squeeze in the juice from half the lemon.
Rub the lemon and oregano paste into the chicken breasts. Take the dish with the potatoes in out of the oven. Nestle the chicken breasts into the dish. Tuck in the asparagus and the bunches of cherry vine tomatoes. Scatter over the olives.
Return the dish to the oven. Roast for 30 mins till the chicken is golden and cooked through – if you insert a skewer the juices should run clear.
Serve the chicken, potatoes and roast veg with wedges of the leftover lemon for squeezing.