Sorry that's my mistake. I forgot that I swapped repositories too, so it's probably not a valid post here. However, I think the second repository I tried had the exact same issues that we were experiencing with roninkenji's So there might be a clue in there somewhere for you Kenji. I'm not knowledgable enough to work it out, sorry.
Anyway, after deleting the container, image and files in appdata I put otherguy/dropbox:1.9.0 in the repository field, put the extra parameters info in and followed the instructions as normal.
I really appreciated the speedy responses from you Kenji. Please let me know if you'd like me to test out your repository again, if you make any changes.