The Landmark Background Protection Area does not include Newham, possibly because no-one ever thought anything that tall would be built that far from the Square Mile
Given that the Manhattan Loft Building is now a fait accompli, the simplest way of restoring the sky background to the view of St Pauls might be to move King Henry's Mound about 100 yards further south!
The Manhattan Loft is in the Olympic Park site, not Docklands, so the relevant planning authority in 2011 was the Olympic Delivery Authority
The London Docklands Development Corporation was wound up in 1998.
The protected area extends 3km behind St Pauls - The Olympic Park is more than twice that distance.