Place all ingredients except the lamb into a blender and create a smooth marinade.
Place the leg of lamb into a clean, plastic bag and spread the marinade all over both sides of the meat. Close the bag and allow it to sit at room temperature for 2-3 hours.
During the last 30 minutes of marinating the lamb, prepare the grill. If using a charcoal grill, prepare the coals so that they form a single layer. You need continuous even heat to ensure the leg cooks evenly.
Place the lamb, bottom side down, on the grill. Sear one side for 4-6 minutes, then flip the lamb over to sear the other side for another 4-6 minutes.
Cover the grill and allow the lamb to cook for an additional 45-55 minutes or until a meat thermometer inserted into the thickest part of the leg registers 55C/130F.
Once the leg has cooked, remove it from the grill and allow it to rest for 10-15 minutes.
Slice the leg into pieces and serve with potato salad or a side salad.
Recipe by Thanks For The Food at https://thanksforthefood.com/grilled-lamb/