I must admit I found this story initially quite exciting - although I live locally I rarely buy the local paper and came across the link via Dorset County Museum's FB page - so they must have given the story some credence.

I have just been looking at Alfred Williams's little book 'Villages of the White Horse' published 100 years ago this summer. He visited and wrote about customs and folk-lore of the 'spring-line' villages going towards Uffington and writes quite a bit about the White Horse. No mention of this figure though or any associated folk-lore. Like someone else said, I'd love it to be true but accept it's highly unlikely.