On: South Kensington station's escalator replacement p...

[SideburnsOfDoom]

The longest single-span Escalators on the London Underground, are at Angel Station.

https://www.youtube.com/watch?v=fFqQOlYE4EE

"the longest escalators on the Underground network, and the fourth-longest escalators in Western Europe"

https://en.wikipedia.org/wiki/Angel_tube_station

Angel is much deeper than Kensington, so the Kensington ones won't be that long.