Upvote:2
This story is not present in the 1815 book, A History of the Western Division of the County of Sussex: Including the Rapes of Chichester, Arundel, and Bramber, with the City and Diocese of Chichester, Volume 1, p.134, which says East Marden is "ill supplied with water." According to A History of the County of Sussex: Volume 4, the Rape of Chichester (1953) pp.107-108, the church dates to the 13th century and none of the parish's other buildings earlier than 1728; it makes no mention of the well. (Note that the word Rape in the titles of these two cited works is a term for a territorial subdivision of (apparently only) the county of Sussex.)