My 3x great grandfather Joseph Mellard born Oct 1849 is Asenath's brother. I have that Benjamin Mellard born Dec 1809 married Sarah Sayles in 1831 and had 7 children. Benjamin died 1875 and Sarah died 1888, but I have not found their burial place, yet. Your great grandmother was the eldest known child, born 1832, Harriet born 1837, Sarah Ann born 1840, James 1845, possible another daughter called Sarah Ann born 1846, Joseph 1849, and Benjamin Osborne Mellard born 1854. Incidentally Osborne is the maiden name of Benjamin Mellard's mother and Asenath Garside is the name of Sarah Sayles' sister (Garside being her mother's maiden name). Hope this helps.
I am not doing much family tree research at the moment due to serious illness within my immediate family and apologise for the time taken to reply to your message - I have not been checking my emails for the last few weeks, as a result of the above situation.