Thank you, Interesting response, the details re my dilemma are fully covered in my post 'Isaac Hardy - Anne Everett' Norfolk lookup board, and could not get any response to my particular query.
The children in Question - all born and baptized within a month: Mary Ann 1873, John 1875, James 1789, and Frances 1791.
I cannot find a plausible marriage re Isaac and Anne that fits (c1782 ish) I am very confident re the baptism events and the names of the parents from the baptism register. And from your comments I agree the marriage of a Ann and Isaac 17 years before the first born is a none starter.
I have looked at all the parish marriage register's surrounding the children's birth/baptism parish. Nothing. You might say a brick wall looms.
Mike.