I have read that owing to the entire Jubilee Line being hors de combat
over the weekend that there are - very unusual this - replacement
boats. They will run East India to North Greenwich after 16:00 on both
days.

On replacement buses the driver never looks at tickets; I wonder will
the admiral look at them on the boat?
Also, I wonder why the time of 4pm was chosen?

Anyway, it might be a nice spin out on a boat, 'for free'.