The calculated distance (air line) between Shepton Mallet and Southend-on-Sea is approximately 143 miles respectively 230 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 Shepton Mallet and Southend-on-Sea has been calculated here.
Air line (approximately)
230 kilometers
124 nautical miles