Unfortunately, Arriva London doesn't have enough Enviro200MMCs to the correct length, or Citaros for the routeI seem to remember the ENX type being uncomfortable and rattly when I travelled on them nearly new. Now they are 12 years old! Not great for a high-profile route. Personally I think a high-spec single decker like a Citaro would be good for an express route. Or at least a newer Enviro200MMC which feel like they have better build quality than the original e200s