Would you like me to send you my Dutton GEDCOM file.
I have put it all together myself from various sources - there are probably a few mistakes. It starts with Rollo (800AD-ish) and goes until about 1820. The web has loads of sites that mention Rollo, and it is possible though probably not so accurate to trace his family back to the 600s. They are all strangely named Kings of Scandinavian mythology !
It follows two main lines. Dutton of Dutton, the mainline, and Dutton of Sherborne, an offshoot, where my interest lies.
I would be interested to have you look over it and see how it compares to your findings.
Let me know if you would like a copy.
If you need a snail-mail address, let me know and I will mail you one - I'm in the UK.