They're saying a whole bunch of nothing to be honest.
No luck for anyone commuting between Victoria and Orpington/Gravesend. Their finite amount of 707s usually make only limited appearances at Cannon Street on a normal off-peak weekday anyway, and with Thameslink capped at Dartford there are no Air-conditioned trains on the Greenwich line except for the small handful of services usually worked by City Beams.
There may have been set swaps but I'm struggling to find any on RTT.
@brad465 might know?
This is only realistic advice for Sidcup/Hayes line commuters. Absence of 707s at Grove Park and Woolwich Arsenal (and by extension, Bexleyheath), few at Bexleyheath, and of course none at Herne Hill