Gloucestershire Records are held at

http://www.gloucestershire.gov.uk/archives/107703/Archives-Homepage.

They hold amongst other items: List of marriages compiled from the Bishops Transcripts 1600-1837

Looking at this family on the 'web' Hugh HYMAN's first son John, carried the middle name of DUNSTON, as did his Grandson. This is possibly a family surname, which was a common practice (and still is in some instances).