Do you have a hooded BBQ?...........if so 3mins a side then 10mins resting in a hot 180deg BBQ but not directly on the heat,just with the lid closed......plate up and rest it for another 5-7mins..........mmmm.......it will be medium rare so add a few mins rest time if you like it medium.........i like mine rare so maybe add another few mins aswell.......LOL
Dan