I received the following response to my email of the 8th October from an advisor in the Lambeth Transport and Streets Call Centre.
Thank you for your email regarding the unsafe and poorly planned railway bridge works at Streatham Common station.
I have forwarded your email onto the Streatham Common station team who are dealing with the bridge works.
Please allow up to 7-10 working days for someone to contact you.
Please do not hesitate to contact me should you require any further information.
As of the 28th of September I have received no further contact from the Lambeth Transport and Streets team.