Thanks to your expert help and advice I have now, a 99.9% operational Green-Field ISP configured and ready to go..... I have one last little question regarding the RADIUS VSA requirement.....
I need to be able to assign the CPE the correct LNS to use. We have 2 x LNS and customers will be split across the two. So, I just need the correct VSA and it's value to use to automatically supply that information with the access-accept packet..... (IPv6 and IPv4 is working perfectly)....
On L2TP LAC, CPE/Subscriber is tunnel based on domain-map lookup(which is associated with username) or via radius return attributes. Domain-map is more simpler in that you know which email@example.com(domain) the LAC tunnels the subscriber towards but your perfer radius, these VSA should do:
Tunnel-Server-Auth-ID. (host name)