As you have changed the default internal network to a different ip range, and bind is incorporated into the system to provide services to the internal network provided by LMCE, it is possible that the bind configuration file needs to be updated to the modified internal IP. There are several places that are hardcoded with 192.168.80.x network address, it could be as simple as changing that file.
I am not sure where it is, and I am away from my system, so I can not look. Some places of interest:
a.) mysql server config = /etc/mysql/my.cnf (this could be in etc, but pluto does utilize its own directory structure for some things)
b.) For mysql mythtv, and pluto db information, there probably has to be a GRANT ALL bit run on the new internal network ip.
c.) NFS shares in /etc/exports are probably still set to 192.168.80.0/255.255.255.0
d.) Samba config files are also probably still referencing the 192.168.80.x network
e.) Apparently bind is also hard set in /etc/named.conf
f.) There can also be a future mythtv issue, check the /etc/mythtv/mysql.txt files (they could be many places, use 'find'
g.) There is probably some changes needing made also to the dhcp server settings as well
I understand this is circumventing the "recommended" settings. And I would never try it myself, but rather than scream "Infidel" at everything, which I know doesn't always happen, perhaps someone who knows the system better than myself can chime in, as to all the places the internal network is configured to the system.
Regards, and Best Wishes,