Enterprise Vault unable to delete Partition

I am using EV 10.0.4 on windows 2008 R2 and we have migrated from EV File System Archiving to a hardware vendor solution.

I have just completed deleting all of our File System Archives using the EV console.

Now when I try to delete a partition under the Vault Store Group I get the message "Unable to delete partition. The partition is not empty"

I had a quick look and there were a number of CAB files and some DVS files still present under the partition (J: drive in my case), despite me deleting all of the archives.

I deleted these files but am still getting the error.

Is there a step I've missed or is there some hack I can employ to get around this error message?