DLP blocking existing file copy to USB device no rules in place apart from standard DLP UK templates

Hi Guys 

Newbie here, just started migrating my user base to Sophos cloud offering, various issues, but biggest one being DLP. I've read what I can find on here, but my issue is different in that I am trying to copy an existing file (any file type) to a USB drive, and I'm being blocked, without a prompt. There are no DLP specific file or content rules in place, bar the standard DLP templates provided by Sophos. I've logged a ticket a few weeks back, but struggling to get anything positive from the support team.

Thanks in advance

Kishan