Royal Marines Band at Bournemouth airshow 2021

The band of Her Majesties Royal Marines (Collingwood) performing at Bournemouth airshow in the lower gardens. I don't know the slow march so if someone could comment that would be appreciated. Mountbatten March -??? Famous song of the British isles John William's mix the day our lord gavest is over sunset rule Britannia god save the queen heart of oak a life on the ocean wave.