Slow Cooker Lamb Roast

• 1 tbsp extra virgin olive oil
• 1 tsp salt and pepper, to season
• 1.5 kg lamb shoulder, with bone in
• 7 garlic
• 2 sprigs of rosemary
• 2 large carrot, cut into 2inch pieces
• 1 large brown onion, quartered
• 500 g small potatoes
• 200 g peas, frozen
• 2 bunch broccolini
• 3 tbsp salt reduced Gravox (or equivalent gravy powder mix)