Okay, well, that was interesting. Did not know about that info file, I've always just looked at /etc/issue before, so thats a useful addition to my knowledge - thanks!
So, the main difference is that we are using the MATE desktop rather than Cinammon, but I cannot imagine that would make much of a difference.
I seem to remember that there is an auto option somewhere in the install script to do with the domain, and I do wonder if we said no, to that and set it manually, if that would make a difference.
Anyway, I am unfortunately on a wait state right now, because my domain adiministrator is not around, so I cannot do any more testing... Can anyone else here say "single point of failure" :-)
Cheers!
Paul.