Readynas Duo V2 cannot access configuration

I have a ReadyNAS Duo v2 connected to my home network with both Mac & PC (Win10) on the network with 2x4TB drives installed.

Firmware version 5.3.13

I can perform write actions (add files, make new folders, rename files/folder etc) to the NAS share drives from the Mac, but not from the PC where I can only read the share files.

Can access config page ReadyNAS [version 1.0.0.271] no problem.  Share folders are all set up with Read/Write access for Everyone.  No specific users are set up.  Protocol-specific Settings are set to Automatic Permissions [checked] and Read/Write Access for all of : Folder Creation Group Rights; Folder Creation Everyone Rights; File Creation Group Rights; and File Creation Everyone Rights.

I can't see anywhere else where to adjust the write permissions. 

Logs attached.

Thanks in advance

Phil