But why: After reaching London bus, there is a swarm of swans across the city near a Border collie flock.
This marketing stunt has been designed to please the tenants in the Fulham Green of a luxury office development. According to Story-full, Hans and his cowboy were a part of the PR.
Source video & images - https://www.sunnyskyz.com/happy-videos/7276/A-Border-Collie-Herds-Geese-Across-London