Question Author
Corbyloon - unfortunately, no it doesn't. I have no problems removing existing people or changing their status, I just can't find out how to add new people that are not already listed.
Like I say, I can email them a link - but that version is not user friendly, I also believe that because they are not "invited", as such and have just received a link, although they can read the files, they cannot edit them, unless they copy the file to their own directory, save the changes and email me the file back to change in dropbox - and this is a palaver!
Thankyou though