Jodie,
Which William Henry GWATKIN is your great grandfather? There are at least two that I am aware of. They are of different generations but have the same common ancestry.
1. William Henry GWATKIN born 1894 to Benjamin Saunders GWATKIN and Emma TWISSELL, married Gertrude.
2. William Henry GWATKIN born about 1863 to Thomas GWATKIN and Ann SAUNDERS, married 1889 to Annie Eliza SAIES.
Yes, I would be interested in the full tree you have dating back to 1580. Does it include sources of where the names and details were found? Send it to me at ratbaker (use the at symbol)juno.com
You may be interested in looking at the GWATKIN One-Name Study as found at
http://treesandstars.com/Gwatkin and perhaps even contributing to it. A few of the certificates for births, marriages, and deaths of GWATKIN individuals I am most closely related to are included there.
Looking forward to hearing from you.
Ruth Ann Baker