So big gap at HOP between the 8:21 and the 08:42 to Lon Bridge? Not great.... To be honest if you are looking to get an earlier train I'd go for before 8am, or (if your employee is flexible, go later, 9am). 8am to 8:45am is getting insufferable whether its BR or Overground.

And once they get the 5 car trains on Overground, but only the first four can open the doors at Canada Water.........