Hi,
The Burial Act of 1853 stopped burials in Church Yards within Urban settings. However, after this date, many registers contain information about ashes being buried, or records of burial services.
In Derby all Church Yard Burials ceased in 1855 on the opening of Nottingham Road Cemetery.
Think you should check with Derbyshire Record Office and ask if Boulton St. Mary's ceased burials
in 1853.
Spendlove