London Walks has suspended their live walks, but they are offering some virtually. They are live and held at specific times. 8 GBP.
One of the walks being offered is on P.G. Wodehouse. If this interests you, I can attest it's very interesting and the guide knows his stuff. I took it as a one-off last September and I was the only one on the walk.
I havent's tried one as I only found out about it today.
Remember, the times given are London time.