The files are uploaded in full. If they are not I can't send them using transfer as dropbox gives me an error.
Unfortunately I cannot ask the client to test the dropbox system. This will sound very unprofessional.
I was posting this as a bug report and I hope dropbox can fix this! I'm sorry but I dont' have time to do dropbox bug testing, and I can't stress this enough, I don't want to. I'm paying for this service and I expect it to work, I can's spend hours testing dropbox systems.