Looking at other questions, I've done the following:

 chmod g+s MEDIA 
 setfacl -R -d -m g::rwx MEDIA 
 setfacl -R -d -m o::rwx MEDIA 

NOTE: MEDIA is a folder I'm looking to set up so that all files/folders added have the same user/group as the parent folder.

In this example MEDIA is owned by the user `Bob` and group `SharedFiles`. The goal is for newly created files/folders to retain this ownership (both `Bob` and `SharedFiles`:

 MEDIA Bob SharedFiles
 MEDIA/NewFolder Bob Bob <BAD
 MEDIA/NewFolder Bob SharedFiles <GOOD

If I create a subfolder whilst logged in as user 'Bob' that folder is owned by Bob:SharedFiles with [rwxrwxrwx] permissions (as intended). All Good!

If I login as Sue, the new folder becomes part of Sue:Sue with [rwxr-xr-x].

If I login from a different machine via a mounted drive in KDE (user Sue) the folder becomes part of Bob:Bob with [rwxr-xr-x].

Now both Bob and Sue are part of SharedFiles, where am I going wrong. I want all users in SharedFiles group to have RWX permissions and I want all files/folders created by users in SharedFiles group to have the same user/group as the parent folder, why does this only happen with the owner on the machine itself.

 getfacl MEDIA/
returns

 # file: MEDIA/
 # owner: Bob
 # group: SharedFiles
 # flags: -s-
 user::rwx
 group::rwx
 other::rwx
 default:user::rwx
 default:group::rwx
 default:other::rwx