The calculated distance (air line) between West Kingsdown and Southend-on-Sea is approximately 24 miles respectively 38 kilometers.
By car or train, the actual journey to Southend-on-Sea is certainly longer, as only the direct route (as the crow flies) between West Kingsdown and Southend-on-Sea has been calculated here.
Air line (approximately)
38 kilometers
21 nautical miles