From TFL’s weekly weekend travel email:
This leaves us with only 2 trains an hour on Saturday and 4 trains an hour on Sunday:
Saturday
Forest Hill to London Bridge at 43 and 13 past each hour from 0643 to 2313
London Bridge to Forest Hill at 10 and 40 past each hour from 0610 to 2340 then 0020 & 0035
Sunday
Forest Hill to London Bridge at 0749, 0805 then at 18, 31, 48 and 01 past each hour until 1231 then at 46, 01, 16, 31 past each hour from 1246 until 2346
London Bridge to Forest Hill at 0731, 0738, 0801 then at 08, 24, 38 and 54 past each hour from 0808 to 2254 t then 2311, 2331 and 2350
Southbound services from Forest Hill on Saturday terminate at Coulsdon Town but on Sunday 2 services per hour terminate at Caterham/Tattenham Corner and 2 at Crystal Palace.
The weekend shutdowns on London Overground look likely to continue until the bank weekend of 29/30/31 August.