OK I changed the paths in sources.xml to include the username and password and changed the host to fqdn.
I then noticed that it was trying to connect to a private ip address on the file server which is not published as a dns entry.
server 192.168.1.1 and it tries to connect to 192.168.199.1 for example.
Updating sources.xml to be the username [email protected] has seemed to fix the issue.
Something is screwy with the name resolution here though as that address it is finding for the hostname does not match any dns entry and it is listed 3rd in nmblookup <hostname>