Frontends caot access remote backend (0.28)

Hi,
I'm a long time Mythtv user. My house has a a number of mythtv/kodi clients, both linux/kodi/mythfrontends and android/kodi accessing a single mythbuntu backend.

This setup had been working well going back many years. I had been ruing mythtv 0.27 since the release of mythbuntu 14.04LTS.

After a HDD failure on the backend server two weeks ago, I replaced the disk and did a clean install of mythbuntu 16.04 LTS. All clients were upgraded to mythtv 0.28 frontends.

In the backend's configuration the host address is set to the fixed IP address, assume 192.168.1.2 - the backend runs fine when restarted.

However, if I check /etc/mythtv/config.xml I see that the host address is stored as localhost - If I attempt to change this to the server's fixed IP address the backend will not start. The log reports a coection timed out error on the fixed IP address, i.e. 192.168.1.2 (!?).

Similarly, none of the front ends will start, locking themselves into an endless loop of exit code 139 and restarts. The log reports a coection time out on the server's IP address. It seems to me that the backend will only run with a host of localhost in the config.xml.

Oddly kodi (16.1) and kodi-pver-mythtv clients access the backend server ok.

I am completely stumped on this. Any hints, tips etc to help me get my head around this madness are greatly appreciated because I do like using the mythtv frontend for some things.

Cheers