Rub the lamb with the olive oil and season with salt and pepper.
Cut 8 small incisions using a sharp knife into the lamb. Press rosemary sprigs and garlic into each incision.
Place the carrot, onion and remaining rosemary into the base of the slow cooker.
Sprinkle over the plain flour and stir to coat.
Place the lamb on top of the vegetables.
Pour the red wine and vegetable or chicken stock liquid around the sides of the dish.
Cook on LOW for 5 hours and 30 minutes or on HIGH for 4 hours.
Remove the lamb from the slow cooker and place onto a baking dish. Cook in an oven pre-heated to 200 degrees celsius (fan-forced) for 20 minutes.
To make gravy (optional step): Remove the top layer of fat from the slow cooker by using a spoon. Pour the remaining contents of the slow cooker into a frying pan or saucepan on the stove-top over medium/high heat. Remove ½ cup of the liquid, cool slightly, and then add 1 tbs of cornflour. Mix until it creates a smooth liquid. Pour back into the frying pan/saucepan. Bring to the boil and then reduce to a simmer. Cook until thickened.