I understand the concern about trains being slashed and about the cuts from Charring Cross (which is a pain for the half dozen times a year I use it) but what I want to know is overall (including the ELLX trains) will be be gaining or losing capacity on the trains to and from Forest Hill and Central London at Peak Time?

It will be a mess during the changeover but I think over time people will adjust where they change/terminate. For those going into the centre of town ELL to Canada Water and then the Jubilee Line will be much preferable (avoids London Bridge!). For those going to the City they can stay on the ELL. So to some extent I think peoples travel plans will adjust. BUT this only works if overall there is at least the same as and preferably more capacity. On this I currently have no idea.

Out of interest I travel into London Bridge and will be affected by the changes, although I do cycle as much as I can to avoid Southern and London Bridge.