1) Toss together the lobster meat, spring onions and parsley in a medium mixing bowl. In a small bowl, stir together the mayonnaise and lemon juice. Add half of the lemon mayonnaise mixture to the lobster. Season with salt and pepper and fold together.
2) Spread 1 side of each slice of bread with the remaining lemon mayonnaise mixture. Top 2 slices of bread with rocket, tomato and bacon. Spoon the lobster salad on top. Cover with a second slice of bread.
3) Cut the sandwich in half, diagonally and secure with frilly toothpicks; serve.