Thanks Teddybear, I appreciate your interest.  I have been to the Norfolk Record Office several times in the last couple of years, and to the Forum, and have tried to read the parish records for St Martin-at-Oak, St Gregory and St Michael-at-Plea  which are prefaced with a "water-damaged" warning. I really found them difficult, if not impossible, to read. On my last visit I was pushed for time and perhaps didn't persevere as much as I ought to have done. One of my cousins also tried, a few years ago, but came up against the same problem.  It is so frustrating!  If you have any ideas I would be most grateful.
Regards,  Lawrence.