Enviro400 MMC hybrid YX66WHK (with regen) - London Central EH68 

With a fast driver (yes, Peckham go fast!), who seems to be going too fast for the bus as it develops weird grinding noises at 1:57. Peckham maintenance...
Also regens going down the hill at 3:37. It doesn't rev as much when doing it as an old style E40H would, but it's unusual to see an MMC do it so eagerly.
This bus was serving route 363 from Crystal Palace to Elephant & Castle.
Operator: Go-Ahead London (London Central)
Fleetnumber: EH68
Registration: YX66WHK
Chassis: Alexander Dennis E40H
Body: Alexander Dennis Enviro400 MMC
Transmission: BAE series hybrid
*regen = regenerative braking. I seemed to get a lot of comments asking me what that word means last time.