(20 Aug 2014, 5:17 pm)Dan wrote Not forgetting that on evenings and Sundays, services 21 and X21 interwork.
Most customers will recognise the bus by its colour, so I think from that perspective, green would work well.
With this 'Angel express', the buses will only be used on the X21 and X46. The Angel B5s are used on the 21 most of the time meaning that it would be pointless including the route up to Bishop Auckland. Especially as the X21 is technically a different service to the 21.