Under Arriva the X1 service was renumbered into the Green Line series as 721 (echos of the former Romford Road Green Line service of the 1950s!) and a number of Plaxton bodied Volvo B10Ms introduced, including 4330, H372 PHK, seen at the new Short Street Arriva depot in Southend.
Photo taken by Richard Delahoy, Short Street Arriva depot in Southend