Yes, I have a Pearce ancestor! Mary Pearce (my 5th great-grandmother) married Thomas Jarvis in 1758 in South Huish, Devon. I do not know anything more about her. I know there were Pearse/Pearce people in the area where she lived but so far I've not determined her parentage. I was hoping that maybe someone here could help me.
Further to your comment on Martha PEARSE ROWCLIFFE. Martha Pearse was the daughter of Philip Pearse (mother's name unknown) and she was married to Philip Rowcliffe son of Andrew Rowcliffe and Joan Harvey.
Tried contact earlier today but this site had been taken over by a rogue site. Your comment about the tree on Genes Reunited seemed a good start except it was not obvious where to find it. Have sent a message to a Cecil there, which is probably you.
I have noticed that my web site is not fully up to date in that I have identified William's parents as Richard & Ann who married in 1841. Unfortunately the FreeBMD register shows that Ann was either Bartlett or Irish and I have not sent for the certificate