Unable to access archived items on shared mailbox
I have a couple of users that are unable to access archived items with attachments within a shared mailbox. The users in question have their personal mailbox as the main mailbox within Outlook (2010) and then have the department mailbox as an additional mailbox. Within Exchange they have Full Access permissions along with Send As permissions on the department mailbox, this is granted via the membership of the department AD group. Within EV the AD group has automatically been set Read, Write and Delete permissions, as expected.
When a user attempts to open an archived email by double-clicking, they see a yellow banner along the top of the email window saying that the email has been archived but they don't see the attachment, only the text placeholder at the foot of the email.
I'm not sure how to troubleshoot this issue any further so any assistance would be greatly appreciated.
We're running EV v126.96.36.1991.
Many thanks. :)