Where does most of the action take place in Black Beauty by Anna Sewell?

Anna Sewell's classic is set in 19th-century England and revolves around the life of a horse, Black Beauty.  The story is a first-person narrative of his life from the perspective of a horse including confusion about the ways of humans.  Most of the action in the story revolves around Black Beauty's various stables. 

His first and perhaps favorite housing is at Birtwick under Squire Gordon.  Throughout his life however, Black Beauty is sold a number of times and treated poorly by many of his owners.  Lady Anne of Earlshall Park is one aristocrat who poorly manages her stables leading to a high turnover and many injuries to the horses.  The cab companies in London also mistreat Black Beauty, save for Jerry Barker.  At the conclusion of the story, Black Beauty arrives under the care of James Howard, once a groom at the neighboring Birtwick estates, who almost killed Black Beauty when he was younger.  Black Beauty spends the remainder of his days happily ensconced at the Blomefields estate.

The earlier chapters detailing Black Beauty's exposure to the world hold most of the action.  This is when he was still stabled at the Birtwick estates.  Black Beauty witnesses the death of his brother Rob Roy, was nearly killed by the stable boy James, saved the life of a man foolishly trying to cross a dangerous bridge at night and almost succumbed to a fire.  Although the events take place away from the estate, Black Beauty always details his pleasure at arriving home.