This from the Birmingham Gazetteer that lists all the Street names. Chain Walk is a lane in Lozells which runs from Lozell Road to Birchfield Road. This is very close to where Ezra lived in Aston.
Here are some more pictures of the area:
|"Houses ready for demolition in Chain Walk, a road with a |
pronounced gradient, joining Lozells Road and Birchfield Road."