Hi,
I appear to have solved the issue.
This is relevant to shared person's Android tablets.
When sharing a folder, the owner can email the shared persons.
The email contains a link to the shared folder and the shared person can open and view the folder ONLY, by following the link.
At the same time as the email is sent a notification is created in the receivers Dropbox. By clicking on the notification, the receiver is allowed to add the shared folder to their own Dropbox. Having done so all changes are synced automatically.
Hope this helps you in future.
Les