This is a response to an old post of yours. I hope it reaches you.
I have been researching Lightbourn(e)(and variant spellings of the surname) in Bermuda, the Bahamas, USA and elsewhere for msny years. I see that I have Mary Rebecca Lightbourn and Rev. James Horne Darrell and their descendants in my database.
I am most certainly descended from the Bermuda Lightbourn(e)s. My 3rd great grandfather was Benjamin Lightbourne who eventually settled in Westmoreland County Pennsylvania around 1790. The surname somehow got changed to Lightburn around 1800. Many Lightburns in the U.S. are his descendants.
I would be happy to share genealogical information of mutual interest. Please let me know.