BBQ Leg of Lamb

1.2 -1.5kg, boned and butterflied (you can ask the butcher to do this) olive oil finely chopped rosemary onion, finely chopped garlic cloves, peeled and minced anchovy fillets, finely chopped salt Black pepper Zest of 1/2 a Lemon sprigs rosemary sprigs thyme Butcher's twine olive oil salt Black pepper