[Facts] Re: last name also first name
I don't believe there exists a specific term for a name which can serve as either a first name or surname, because technically *any* name can serve as either.
Considering the fact that most inherited surnames evolved out of descriptive suffixes added to people's given names, the closest term for a surname which resembles the father's actual given name would be "sire-name" or "patronymic".
In the example which you cited (Robin David), "David" might be either a "sire-name" or a "patronymic".
If the name-suffix is derived from the female parent, then it is called a "matronymic".
There was a feminist movement some years back which advocated women discarding their patriarchal-inherited surnames and substituting these names for either their mother's given name, or for their mother's given name in the possessive form with the Scandinavian suffix "dotter", "dottir", or "dot" added on (indicating "daughter of"). As in "Margaret Marysdotter" or "Margaret Marysdot". Obviously, it never caught on.
-- Nanaea