In a small saucepan over medium–low heat on the stove, warm the garlic and butter until the butter melts. Set aside about 2 tablespoons for brushing on the buns.
Prepare the grill for direct cooking over medium heat (180°C to 230°C).
Carefully cut the lobster tails lengthwise in half. Season the meat with a little salt and brush some of the garlic butter over the surface of each one. Brush the cooking grates clean. Grill the lobster, meat-side down first, over direct medium heat, with the lid open, until the meat is opaque, 2 to 3 minutes. Turn the tails over, brush with more garlic butter and continue to grill until the meat is slightly firm, about 3 minutes more. Remove from the grill and let cool completely.
Carefully cut the lobster tails lengthwise in half. Season the meat with a little salt and brush some of the garlic butter over the surface of each one. Brush the cooking grates clean. Grill the lobster, meat-side down first, over medium heat, with the lid open, until the meat is opaque, 2 to 3 minutes. Turn the tails over, brush with more garlic butter and continue to grill until the meat is slightly firm, about 3 minutes more. Remove from the grill and let cool completely.
In a large bowl combine the mayonnaise, tomato, scallion and lemon juice. Season with salt and hot sauce. Remove the lobster meat from the shells and cut into 1 centimetre pieces. Add the lobster meat to the mayonnaise mixture. For best flavour, cover and chill at least 1 hour. Mix in the chervil just before serving.
For standard buns, using a serrated knife, trim a very thin layer of the crust from the sides of each bun to expose more of the inner crumb and give them a slightly rectangular shape. (Lobster rolls are traditionally served in split-top buns.) Reheat the reserved garlic butter and brush it on the outside of the buns. Toast the buns over direct medium heat until golden brown on both sides, about 1 minute, turning once.
For standard buns, using a serrated knife, trim a very thin layer of the crust from the sides of each bun to expose more of the inner crumb and give them a slightly rectangular shape. (Lobster rolls are traditionally served in split-top buns.) Reheat the reserved garlic butter and brush it on the outside of the buns. Toast the buns over medium heat until golden brown on both sides, about 1 minute, turning once.
Divide the lettuce and lobster mixture among the buns and serve.