Before the storming of the breech at Badajoz an officer encourages the troops by singing 'Heart of Oak'. This is the march of the Royal Navy and given the traditional inter-service rivalry between army and navy it's an unlikely choice for an army officer.
When Hakeswill gets head-butted by Harper, his head is bleeding above his left eye. But when he goes out and gets knocked to the ground the cut and blood are gone.