Help needed please:

My 6th great-grandfather Benjamin Vanstone married Thomasin Weeks in Iddesleigh, Devon on the 27 Apr 1768. That much has been confirmed on many FH websites, the Iddesleigh parish registry entry states that Benjamin was from Winkleigh and Thomasin was 'a minor'. I've managed to trace all of their children, including my direct ancestor Benjamin Vanstone born 1773 (Iddesleigh) but, I haven't been able to find any parents or baptism of his father Benjamin Vanstone who married Thomasin and died in Nov 1799. This is an ongoing search (my brick wall) so any help very gratefully received.