Hi Stanford,
My family line links to yours via the Son's of Bartholomew b1714. I decend from George, your Thomas' brother. I have been working to push the line further for more than 10 years. I have a good idea where Ralph came from but unfortunately the parish records do not exist to prove it one way or the other. A DNA Link to another Harrison Branch from the area, prior to our Ralph may be the only proof we will ever be able to get.
Kind regards
Brian