I believe that you do not have the correct permission in the subfolder as that structure already existed and was probably created by a different user under OE. If you were to ssh into the LE box and CD into the mount point I bet you cannot create a directory under the same folder.
Simple solution is in the SSH session to the LE box run chmod +667 /media/myshare/Dir_with_no_access or whatever you mounted it to.On the QNAP side also make sure ACL permissions are turned off on the share, and that guest has FULL Access which flows down to all folders.
Oh finally I found the problem. The problem wasn't within the "users and group permissions" as they both had the same. But there was another category within the permission settings that I totally missed. The "NFS Host Acess". Changed the allowed IP to "*" and now it works fine, I have acess!
Thanks for all help anyway!