Thank you. I've given the categories a whirl and it seems it does handle this partly.
Unfortunately for it to work for us, it would need another set of permissions on the category settings, IE which usergroup to "Deny" to.
All our registered members are in the registered usergroup (which has the viewing permissions) and the junior ones get added to a secondary usergroup.
With the default xenForo granular style of permissions, we can revoke permissions based on usergroup, and it's that feature we could do with on the Gallery. A revoke option
Thank you
Also, has anyone got a stream from this working in xenPorta? I'd love to be able to stream some photos to our homepage but I've no idea how