Hi Mary,
I couldn't find the marriage either, which is why I wondered whether John's birth was illeg., and that for once the IGI had him under the father's name because it was included at his bapt. But the "Mary Craine als. Kerruish" looks as though they were married - or said they were to a vicar who didn't know them?
The next illeg. birth to Mary makes this look a possibility? - And she was Unm. in both 1851 & 1861 so my guess is more likely never married.
Sue