There is a frequent fast service direct to Clapham Jct/Victoria from East Croydon.
I find that the best way to get to those parts (avoiding central London).

East Croydon is an important rail interchange for us as is London Bridge as is Lewisham.
If we had frequent trains running directly to all these hubs, then we should think our rail transport needs well considered.

Despite Lewisham being the major local train station/interchange, we still have no direct link (a docklands extension up to East Croydon via HoP and Forest Hill would have been popular imo).

And of course our existing routes to London Bridge and East Croydon are due to be strangled by the ELL.