During Herschel's star survey of 1797 he discovers an unexpected comet, further checks show that the comet is not on a ballistic trajectory but is under power, it will reach Earth in early 1798 somewhere in the Atlantic. The giant metal object is met by a squadron of the Royal Navy under the command of Admiral Sir John Jarvis , and nothing happens the metal globe settles onto the sea and seems to do nothing, close inspection reveals that several holes in the upper surface have been caused by collisions with asteroids. Vast chambers stand empty with some remains of shatterred glass cylinders which once filled them but unfortunately the contents seem to have been lost to space, despite its size the object seems to be nearly weightless and the fleet is able to tow it to St Helena where study by the Royal Society commences.
Other nations are curious but are able to gain no information from the British as to their investigations, finally amidst the fighting of the Napoleonic wars the Franco-Spanish fleet under Villeneuve is sent to attack St Helena and is destroyed by a Royal Navy squadron under the command of Lord Nelson in 1805. Despite his victory Lord Nelson does not return to London and it is noted that Lady Hamilton moves to St Helena.
The first sign that the British have had results occures in 1812. The French are marching on Moscow, American troops have somewhat incompetently invaded Canada and Lord Nelson returns commanding the experimantal Landship squadron of the Royal Navy. Napoleons Advance on Moscow ends in 2 hours of fire and death, France surrenders a few weeks later, the Americans surrender months later when the first of the landships emerges from the Potomac and places the city of Washington DC under it's guns.
It seems that by the time of the Battle of St Helena the British had made some progress with the object which had been determined to be a colony ship of a race called the Breen. In fact contact had been made with a thinking machine inside the ship which had been shocked to discover all of its colonists had died in an accident , it had provided medical aid to the British following the battle and many British, French and Spanish sailors who would have died had been saved. Finally the Thinking machine had agreed to uplift the human race and as the Breen had been a monarchial race it was happy to help unify the world under the British crown.
By 1820 treaties , marriage and the deployment of the invincible Land ships had brought the world under a single national rule and the work of educating the population and producing the Breen technology had begun. Many parts of the colony package were automatic and so some mines , and shipyards had been deployed while the limited manufacturing base worked on uplifting humanity
Set up
1 billion population
Several shipyards and 200 automatic mines, alien ruins on Earth and a conventional start with no conventional military but a small contingent of TN Ground forces