There were a number of William Hall's born in Devon on or within a yr of 1848. https://familysearch.org/pal:/MM9.1.1/M7YY-5R5
https://familysearch.org/pal:/MM9.1.1/XSW6-3Y3
https://familysearch.org/pal:/MM9.1.1/M759-4GJ