sudo mediatomb -i 192.168.80.1 -p 3877 -c /etc/mediatomb/config.xml
As if by magic mediatomb seems to be running, terminal shows it and i can now access mediatomb via the webadmin page!
I think it probably wants a final command along these lines;
sudo mediatomb -i 192.168.80.1 -p 3877 -c /etc/mediatomb/config.xml -d
Some success. I just need to work out how to get mediatomb configured to accept the Linux MCE file structure in a neat way, and then where to script the above command so it runs automatically in the background at start.
For anyone after a not very elegant solution, from within the mediatomb webadmin you can manually add the Linux MCE folders to the database (via the Filesystem tab at the top of the lefthand pane). I am sure there is a more elegant solution, but for now at least I have Upnp up and running.