From the photos i've seen the tree bars on the Wright deckers look useless, but trees shouldn't be hitting them anyway. With the mayor authority running the buses you would hope any works would be done quicker.
Street Decks are some 6" taller than E400s hence a different profile for the overhanging trees.
Streetdeck = 4.395m = 14ft 5in E400 = 4.2m = 13ft 11ins