Buster makes a very valid point regarding onward travel from Luton. National Express coaches seem to come and go every couple of minutes. Pushing my way through the crowds at the bus station it is very clear that not many passengers are actually English.
It is a bit of a chicken and egg situation for Southend as what do you provide first, the coaches or the passengers to use the coach network. Southend's location does not help either as it is not a natural route for north and south coach travel.