I’ve emailed TfL to ask them to consider adding an OSI between City Thameslink and St. Paul’s on the basis that this will significantly ease connectivity from Elephant & Castle and London Bridge to the Central Line eastbound during the Northern Line closure from Kennington-Mortgate.
As it’s now shown as a dotted-line on the Tube Map, it seems likely that many people will use the link during this period; potentially being charged more than their pre-disrupted journey.