Unable to delete a file (A windows backup file on an external drive)

I had an old drive I used ot use for windows backups that I copied onto a new NAS device (WDCloud) and it has a few files/directories on it that were associated with the old Windows laptop. SO I am trying to tidy up the drive and remove superfluous files but there is 1 file in the directories that I cant get rid of no matter how much I try.

Delete in Finder just comes up and says I do not have permissions to delete : The operation can’t be completed because you don’t have permission to access some of the items.

So I check Info and I see that 'everyone' only has read permissions - I try to add myself with more right but I cant seem to get the user name right even though I type it right - I am sure.

So to heck with this I will jumo into terminal and remove it there ... but nope that wont work either ..

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gordons-MBP:400GB Drive GordonK$ ls -l

total 8

drwxrwxr-x 1 GordonK staff 264 8 Apr 12:26 IBMX200

-rwxrwxrwx 1 GordonK staff 528 28 Dec 2016 MediaID.bin

drwxrwxr-x@ 1 GordonK staff 264 28 Dec 2016 RECYCLER

drwxrwxr-x@ 1 GordonK staff 264 28 Dec 2016 RRbackups

drwxrwxr-x@ 1 GordonK staff 264 28 Dec 2016 System Volume Information

drwxrwxr-x 1 GordonK staff 264 28 Dec 2016 boot

gordons-MBP:400GB Drive GordonK$ rm MediaID.bin

override rwxrwxrwx GordonK/staff uchg for MediaID.bin? y

rm: MediaID.bin: Operation not permitted

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Any suggestions for other commands to try ? I am an admin of the Mac.