I joined a call back in Feb 22 with Southern Rail which was hosted by a Lewisham MP - I think Vicky Foxcroft. At that point theat Southern were running 2 trains ph on the East Croydon. Lots of concern and harumphing, but the general Southern read out was not sufficient resources to run 4 trains (back in Feb 22 the traffic was alot lower than now of course). I do remember concerns being expressed about the lack of routes up to West End from SE23 and that Southern did say, oh, perhaps rather than running 2 trains per hour to East Croydon we could swap them to for the Lon Bridge/Victoria route which of course is what happened - the only benefit being they are 10 coaches rather than the 5 coaches we had on the EC route.
I can't say how much Ellie Reeves or the councillors have or have not done, though under the present rail industry set up, are Southern going to change course because of noise from (currently opposition) MPs or councillors. May be worth people emailing MPs / councillors to try and stir things up.
Fundamentally though, Southern do not and will not want to put resource into the trundlers running within Zones 1-6 as they make more money on the longer routes; plus of course on our route they will say "oh you have the Overground".
The only way out of this that I can is a major structural change - my preference would be for all rail/overground routes that are within Zones 1-6 are given to TFL. Not saying that is a panecea but at least there would be one body to make balanced decisions for Zones 1-6 routes.
But difficult to see any major change this side of a General Election.