The Old Mere
The original Westbury horse has, in the past, been illustrated facing right. This is now generally accepted as being a print error during the original pressing of Camden's Britannia (1772). This first incarnation Westbury's white horse was said to have been cut within living memory of 1772 (1700-1720) although the exact date is unknown.
The story goes that the horse was cut to represent King Alfred's horse, on which he led the victory over the Danes in 878 in the local area in the battle of Ethandun. The original horse was reported to have been 96 feet (30 meters) long by 32 feet (almost 10 meters) tall . It was first documented in 1772 and a sketch of the horse at this time exists. Assuming that this is an accurate sketch (show here transposed to make the horse face left), It was a strange looking creature. You can almost forgive George Gee for having it re-cut in 1778!
Sketch of the first Westbury Horse by Richard Gough which was published in the 1772 edition of Camden's Britannia.
Recently, another image of the same horse has been discovered (below). It came from a map produced in 1773. This also shows the horse facing left. This would tend to back up the historians who argued that the original horse did indeed face left (Plenderleath in 1885 and Marpels in 1949).
I have used some hi-tech jiggery pokery to rotate and enhance the horse on the map above. As you can see, it bears more than a passing resemblance to a left facing version of Richard Gough's original sketch:
