I have just looked at your tree and it shows we branch off when you get to Joseph b1842. My line goes from Charles to Joseph's sister Eliza where she has base born son Arthur George Ponton Amor born 1859.

I was able to find Thornill's birth records in Corsham that showed his parents names and also the marriage records for William and Agnes Humfrey. If you click on my name in the email and then click on profile then click on family tree you should be able to see the documents that I have attached and bring them over to your tree. If that does not work then if you give me your email address then I can add you to my family tree list so you can view it.

Where in Devon do you live? I live in Kelowna, British Columbia, Canada.