Hi Vicky, I am really excited to have come across the photo you posted on Ancestry of the gravestone of Benjamin and Annie Gibbon. It's rather fortuitous since I have been collating what little info I have on that side of my family to try and find some evidence when we go down to Pembrokeshire at the end of the month. They are my 3x great grandparents on my paternal grandmother's side of the family.
I have managed to find Benjamin's parent's, John and Jane, from the Baptism records of their son William and their other children (on FMP) but so far have had no success in finding any details for them.
It will be interesting to see how you and I are related, if very distantly!