<<The LDS has only filmed a few years of civil records
for the parish during the Napoleonic era.>>
Jb has already given you valuable information but I thought I'd add my experiences.
I'm not researching your area but your (above) sentence struck a chord with me. You have to be very inventive with 'keywords' when searching the LDS library. I had viewed films which should have contained my paternal family information but didn't and thus thought the records must have been destroyed. Surfing the web showed the parish I was interested in had amalgamated - I made contact with the vicar and also the dioces archive who were successful and I received the same paternal family baptism information from both of them (** see below). I then turned my attention to looking for the maternal side in a nearby parish and luckily the LDS had so many films I was spoilt for choice. I viewed 2 films showing both church records and court address records of several villages and there sprinkled throughout both films was the village court records and the church records of the paternal line I had not been able to find. Similar to your situation, there is no mention on either of the film descriptions of that village name or its amalgamated neighbour.
<<The problem is, soon after my 2ggrandfather left, the
pastor at the time assembled an informal family book
or parish directory which does not include my
ancestor. Like parish directories of today, it
probably included those currently in the parish, not
who were born in the parish.>>
This describes the building/people count which each parish had to conduct each year and is officially called "Court Address" Records. The Court Address film I viewed brought a bonus of naming everyone in the household of another of my families, unfortunately my paternal family was only a 'head count' to their village vicar.
** I thought they had both sent me the same information of the wrong family but after checking English records it seems my gt.grandfather was also having to produce incorrect official documentation probably initiated by a vicar who liked a few tipples of the local brew. The vicar had entered his baptism records incorrectly by writing the child's name in the father's column and the father's name in the child's column. This was never corrected and it was only after finding an existing original document of the father's 2nd marriage that it emerged he couldn't write.
Rena in England