The listed coordinates will take you to Fort Frederick, built by British soldiers in 1799 and now a national monument. It is said to be the oldest British-built building south of the equator, and was named in honour of the Duke of York, Commander of the British Army. Commanding a good view of the whole of Algoa Bay, its eighty foot square and nine foot high walls contained a powder magazine holding 2000 lbs of gunpowder. The heavy armament consisted of 8 twelve-pounder guns and a full complement of 350 men were housed in nearby barracks. As with all of PE's 19th century fortifications, the fort has never fired a shot in anger. Outside the wall is the grave of Captain Frances Evatt, commander of the fort from 1817 to 1850.
Oh, The grand old Duke of York,
He had ten thousand men;
He marched them up to the top of the hill,
And he marched them down again.
And when they were up, they were up,
And when they were down, they were down,
And when they were only half-way up,
They were neither up nor down.
You can check your answers for this puzzle on Geochecker.com.
A well earned FTF to team simplr.