The 2 annotated c1930 might fit, despite the apparent date discrepancy:
LT 000512/001-002 Development Proposals – Possible Extension beyond Elephant & Castle Circa 1930 LT 001087/011 Planned Extension to Camberwell & over Southern Railway Routes - Statistics , Correspondence and Maps Circa 1930
There may well be something more concrete in that archive, so hope you can access it.
You probably know how, but here's a link just in case:
And if you call me brother now,forgive me if I enquire, just according to whose plan?-Leonard Cohen Story Of Isaac We don't want to save the world, we want to kill the human race-The Meteors Teenagers From Outer Space