I can tell you that the records from the 1st Boardmills Presbyterian are still held at Trinity Church there! I've been in touch with Rev. James Hyndman there & he would like someone to search the records with him. I'm in New Zealand, so I've been searching for someone to do the honours! Our line is descended from John & Jane Maxwell nee Brown who wed in July 1800.
Specifically we're looking for the birth of their son Thomas who emigrated to NZ about 1826, & any other children they may have had, - perhaps a Robert who emigrated to Pennsylvania in the U.S..