Dora (and Jon Cave) I am also a direct descendant of Major General Gladwin through Joshua Jebb who was my 3gs grandfather. The name "Gladwyn" (note the alternative spelling) has been used in the family since at least my g-grandfather,John Berridge(Beveridge?)Gladwyn Jebb and my children have it too. Do you have any information on the Gladwins before Thomas Gladwyn? The web is so informative now that I would think we can all get access to any records of the name but it certainly makes it easier if a family member has a tree.
Your 5th cousin once removed (I think), Nicolas S Gladwyn Christian