Preheat the oven to 220°C conventional bake.
Green herb paste
Place all the ingredients, except the oil in a food processor and mix for 30 seconds. Drizzle in the oil until it forms a paste. Season and set aside.
Open out the lamb, trim off excess fat and skin and place with the flesh side up, . Spread over the green herb paste. Starting from one narrow end, roll up neatly into the best shape you can and tie at intervals with kitchen string to secure.
Place lamb in a roasting dish and place in preheated oven. Roast for 20 minutes, then reduce the oven temperature to 190°C and roast for a further 40 minutes together with the shallots and potatoes. Transfer lamb and roasted vegetables to a warm plate, cover loosely with foil and keep in a warm place while you make the gravy.
Beetroots and dressing
While the lamb is roasting, prepare beetroots. Put the vinegar and maple syrup in a bowl and whisk in the oil. Season with salt and freshly ground black pepper. Set aside. Boil beetroot in lightly salted water for about 35 minutes or until just tender when tested with a skewer. Peel beetroot either by using a small sharp knife, or by using your fingers to rub off the skins under slowly running cold water. Cut beetroots in half and place into the dressing and toss. Set aside. .
To serve: Slice lamb and place down the centre of a large platter. Surround lamb with roasted shallots and potatoes on one side and beetroot and steamed green beans on the other.
Serve with a jug of gravy.