m 11 Aug 1817 to John Buller at Banbury.
Unfortunately it has proved impossible to trace the birth of Susanna, even though there was a Derry family in Banbury during the 1790s, parents John and Susanna. So it seems logical that they did have a child called Susanna, but there is no trace.
The only registered birth of a Susanna Derry was in 1801, but she was a gypsy with no specified parents. There is another family called John and Susanna derry in Marden, Herefordshire, who did have a daughter Susanna Derry, but they also had other children a the same time as the Banbury family, so it couldn't be them.
Then, after the marriage, there is no further trace of Susanna nor John anywhere.
A mystery.