Good morning Richard,
It would depend on a couple of things. Are you connecting to an Exchange
server? Or do you use a PST?
If you connect to an Exchange server and IF the admin has Deleted Item
Retention turned on, you *may* be able to recover the folder. Open your
Deleted Items folder and click on tools, then scroll to Recover Deleted
Items. If that menu option is not there, then this option is not available.
If you use a PST, check the information listed here: