As far as I know there are no scarffe baptismal entries in Santon - at this period the name is almost entirely restricted to Lonan with very few in the adjoining parishes
If the various baptismal registers are complete (and there is some question re Lonan c. 1793) then there are only 4 contenders all born in Lonan with the most likely the son of james scarffe + cath kneal - if you look at my will summaries + the scarffe wills on Brian's site I think most are covered - possibly those remaining might shed some light but as the Museum is closed for the next 9 days I can't do any checking till next week.