I always like to give John Rogers a mention if London walking video creators come up. He has a different style to Joolz, slightly more laid back and thoughtful. Some walks in some really obscure parts of London, many out here in north east London. He lives a couple of miles from me in Leytonstone I think.
He has written two good books. His work ties into the psychogeography movement and is quite engaging prose. His walks detailed in the books are more psychogeographical essays than guides. He's a bit easier to read than Iain Sinclair, another author in this genre. I haven't done any, though I know the areas he covers local to me from walking.
You can read about John Rogers and click through to buy his books on Amazon -
https://www.amazon.com/stores/author/B00GOF04ZQ/about
He's on Youtube here -
https://www.youtube.com/@JohnRogersWalks