OK I cracked it ! I had to explicity tell the server that it was allowed to forward mail generated by itself. So in this case: Server 1 forwarding to server 2. Server 1 had to have 127.0.0.1 in its allowed list in the relay settings. I don't remember it being that way in previous versions, but hey...

@ Paul. Good advice. Thanks. I did that and it connected. Still unsure now what the issue could be though. I can only assume that I must have configured something wrong. Hmmm ...... Guess that's my task for the day. Firewall, etc Any ideas welcome. Regards Dave

Now the host is telling me that they aren't blocking port 25 after all. They said that they had already opened it up for us on our vlan. @Paul - I know that they weren't being mean, I know it's best practice etc etc. I was just frustrated when I wrote that ! lol So end result is that I am...