The Sidcup line up services are starting a minute earlier than currently, being 09, 24, 39 and 54 past the hour from Crayford instead of 10, 25, 40 and 55. They still get to London Bridge at the same time though, so obviously they feel more padding is needed in the schedule.
Southeastern also appear to be bringing back the Summer specials to/from Ramsgate via the North Kent line. The Saturday service starts as early as the 24th May, with 2 trains a day each way. The Sunday service doesn't start until the 20th July, with 1 train per day.