The first question is if it's an autograph of his.
He apprenticed at Heath House stables, Newmarket and lived there until 1884
http://www.heathhousestables.com/heritage-and-history/
The piece looks a bit more like an address from a letter to him than an autograph. And return addresses weren't as common at the time.
Of course, being British, and that he was pretty well tied to the stables, that may be an inscription. I don't know what would have been typical then in Britain.