"at the distant fields and hedges of Sheppey"
The Isle of Sheppey is a stretch of land in the Thames Estuary, just off the north coast of Kent. It consists of three separate islands: Sheppey, the Isle of Harty and the Isle of Elmley. It lies to the northwest of Whitstable.
The strip of sea which separates the Isle of Sheppey from the mainland is known as The Swale.