Hello again,
Looking at the death of William in 1884, therefore born 1795, if age 89 at death. Agewise, PERHAPS he is a brother to Anthony Clarke who was born abt 1788 and died Sept 8, 1862 in Ballymulderg. I have Anthony's mother as POSSIBLY Alicia aka Ally. This William is a better age to be David Ramsay Clarke's father. Do you know when David Ramsay Clarke's sister Alice was born? I have an unconnected Alice Clarke born 1827 with father William who married Samuel Richey in 1854. This may be your David's sister. There may be a connection here.
Anthony's first son is William baptised 1812, so his father could also have been William, using the naming pattern. Anthony has a son David who died a bachelor in 1897.
Peggy