Departure out of Birmingham EGBB BHX, two attempts with a Boeing 737-800NG

Departure out of Birmingham EGBB BHX, two attempts with a Boeing 737-800NG. We lined up on the RWY, ready for departure but got to confirm a special proceedure before departure. Therefore we vacated the Runway and went for another departure after going through some proceedures. Flight continued to Barcelona LEBL BCN.