Hi there. I’m a bit confused. Repairs to your own flat are your responsibility. If the repairs are the consequence of problems in another flat then I *think* your Camden Council buildings insurance should cover this and you claim on that, calling the insurance company directly (and they will let you know how to proceed).
I could be missing something here and suspect I am!
For what it’s worth, if you think that some Camden Council service is failing and not responding in a timely fashion, then the most expedient is to lodge a formal complaint: Here’s the Leaseholders’ Forum guide: https://www.leaseholdersforum.org.uk/guides/complaining-effectively/
Best regards, Paul Ginsberg