Seen in Holborn on former Red Arrow route 521 in October 2016 is Citaro MEC49 (BT09GPF).
Picture ref B4620
By July 2018 new electric buses had displaced the Citaros from the Red Arrow routes, some were dispersed to other Go-Ahead fleets but MEC1 (BG09JJK) is seen in Blackheath on the Dartford Tunnel 108 route.
Picture ref C1300
The following month MEC8 (BG09JKE) was also on the 108 in Greenwich.
Picture ref C1877
Another 108 Citaro a year later in North Greenwich, MEC30 (BD09ZVV).
Picture ref C5276