Hey Paul,
have you tried:
a). changing the permissions on the folder manually via FTP, i.e. right-clicking on the folder in your FTP client and choosing “Preferences”, “File Permissions”, or similar, depending on your type of FTP client and setting all checkboxes into the “checked” state?
b). asking your hosting provider to delete the folder from their side?
Sincerely,
Andrii / Satori Studio