Eugh now I feel like a muppet!!!
Its important to have the right ports, with UDP and TCP setup as per that list. For my server, I set the client IP’s to only allow from my backup server (as that’s the only one that should be requesting). Also you need to lock down the the admin panel port to make sure no nasties can get in and grab your data
ARGH I feel so stupid for wasting so much time and not checking out that article!