Please see the following link for more information;
On-Site
https://www.diamond.ac.uk/Users/Experiment-at-Diamond/IT-User-Guide/At-DLS/Access-data.html
Off-Site
https://www.diamond.ac.uk/Users/Experiment-at-Diamond/IT-User-Guide/Not-at-DLS/Retrieve-data.html
Within 40 days of session
Use Globus online
After 40 days of session
Use TopCAT/icat (https://icat.diamond.ac.uk/#/login)
https://icat.diamond.ac.uk/#/help
NB. The root directory for your visit is named "topdir"