Mr. C. E. Ponting writes that in 1889 he noticed that this hill appeared from the Pewsey Vale of a bright yellow colour, caused by a mass of yellow Ladies’ Fingers (Lotus corniculatus?) in flower, with which the whole hill was covered. He suggests that this is the origin of the name.
Possibly not so comprehensively explained as the other idea on this page. Some may think it more convincing. But where’s the ball.
In the Wiltshire Arch. and Nat. Hist. Magazine for 1897 (v24).
How lovely ... I always thought the name was to do with the sun.
To be honest June that's the best explanation so far, it certainly beats ball-less floral explanations and ufos.