Just to update, everything is working perfectly now, yesterday I modified the BI service to be run as the local user and now everything is running as I expected it to in the first place.
I have an HP Microserver upgraded with an i5 CPU running unRAID with pfSense and UniFi and the Windows 10VM running BI all running smooth with 15-18% CPU usage, my clips/alerts are going to the SSD on the Microserver and then being moved to the array on the Microserver after 12 hours.
Many thanks for everyones help, the issue was basically the BI Service running without access to the unRAID array.