Southeastern have offloaded 25x 465s and 27x 466s from the MetCam side, which is 154 carriages. 30x 707s brought in 150 carriages, then 13x 377s added another 52 carriages, so this gave SE an additional 48 carriages, equal to 12x 4-car units, vs their pre-covid fleet size.
However, this is not accounting for the first BREL units going to scrap and some in de facto storage, so at the moment the total is probably close to zero net change. At the moment this is not a problem, however, a new fleet order needs to get a move on as Southeastern will need it ASAP, especially with improvements to the timetable from December increasing demand, and in turn maintenance costs, on the fleet they do have. The additional 377s haven't actually replaced many Networkers, as the Maidstone East line since 2022 has seen a major capacity uplift with the Charing X services, and looks set for evermore increases in December too, with the line returning to at least 3-4tph all day west of Maidstone, something not seen since pre-HS1, an unlike then, almost all services are 8-car, not 4-6 car.