Surely it would run to Crofton Park rather than Honor Oak, unless they plan to lay a new track bed?
They were considering tunnelling. Which would add a new line without removing existing capacity.
If you trawl back through Hansard, for most of the 1990s the extension of the Bakerloo line from Elephant & Castle was the preferred option of our illustrious Member of Parliament. No wonder it took so long for the East London Line project to get off the ground.
It would have been a better option for Forest Hill.
However, I think Lewisham Council favour the Bakerloo line being extended to Catford along the existing railway tracks to Hayes.