These coordinates didn't only show the way to a very special horse, they also lead to a valuable object, that was offered as a prize in a video game.
What was the name of the game?
The coordinates are
the Litlington White Horse
And the video prize was
Pimania by Automata. They gave a prize of a golden sundial worth £6,000 for the first person to solve the various cryptic clues to its location you had to meet the authors, the day of the year and the time, that were hidden within Pimania. The location was The chalk horse at Hindover Hill near Litlington, East Sussex.