Teriyaki Lamb fit for Royalty

Ali and Craig Brown were kind enough to share this recipe and I of course want to pass it on to you… thanks guys, that was some dinner!
Ingredients
1.5kg boned leg of lamb
Medium sized onion cut
Teriyaki sauce-(home made or from a bottle)
Method
Open up the piece of lamb to make sure that it is approximately the same thickness overall to ensure even cooking times.
Lay the onions on a non-stick baking dish with their cut sides facing skywards. Place the lamb in the dish, surrounded by the onions. Drizzle the Teriyaki sauce over the meat and rub it all over with your hands. Leave to marinate for as long as possible. We try and leave it overnight for best results.
Take it out of the fridge approximately half an hour before cooking.
Fire up the barbecue and wait until the coals have turned white
Add the whole piece of meat plus any onions that you want to roast in the middle of the heat.
Keep an eye on the meat and keep turning it. It should take approximately 30 minutes to cook.
Salad Ingredients -(This recipe is great as you can add any salad ingredients that you like or have in your fridge.)
Tomatoes
Spinach and/or lettuce
Celery
Pepper
Cucumber
Feta cheese
Beetroot
Bulgar wheat (cous cous or quinoa can also be used.)