This is a longshot - I think I lost my pink fitbit while walking from Clapham South Tube (bus stop actually) to home. I was dealing with jackets and umbrellas and toddlers!
I walked along Nightingale Lane, Clapham Common West Side and then up Walsingham/Roseneath.
If you happen to find it, I'd be grateful. I just got it a couple weeks ago!!!