The calculated distance (air line) between Buckhurst Hill and Southend-on-Sea is approximately 30 miles respectively 48 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 Buckhurst Hill and Southend-on-Sea has been calculated here.
Air line (approximately)
48 kilometers
26 nautical miles