I know it's is way over due as replies go but I work at Tom James and can hopefully enlighten.
Tom James is the main company name and under that names it owns Oxxford, used for when we do fully handmade, and Holland & Sherry, used through out a lot of our semi-bespoke (or custom) and all the way up to fully bespoke.
We also have built and run our own mill in Chile to go along with he mill that came with Holand & Sherry when we bought it.
Hope useful. Please let me know any other questions.