Preheat over to 375°
Onto a clean cutting board, place the Aussie lamb rib roast, and using a sharp knife divide into single bone sections. Place the cut lamb rib sections into a large bowl and coat with 1 1/2 tablespoons of oil and 1 1/2 tablespoons and a 1/2 tablespoon of Old Bay seasoning.
Cut, chop, and quarter all of the vegetables and potatoes you're going to use and set them aside. Place the veggies into a large bowl and add 2 1 /2 of oil and 1/2 tablespoon of garlic pepper and a 1/2 tablespoon of Old Bay seasoning. Toss with your fingers to coat and season the vegetables evenly.
Place the potatoes onto the sheet pan and place them into the oven and cook at 375° for 10 minutes. Them remove the sheet pan from the oven and add the remaining veggies and lamb.
Put the sheet pan into the preheated oven on the center rack and cook for 35-40 minutes.
Remove from the oven and serve.