Update. I stopped and restarted the endpoint process on the UTM, the state of the PC now shows as online and Status as OK. The PC still shows the Sophos endpoint as failing to update.
I will attach the UTM endpoint log extract.
2012:05:05-11:41:18 cats-kingdom epsecd[18350]: I Epsec::Utils::Logging::_log:59() => id="4231" severity="info" sys="System" sub="epsecd" name="Handled SAV event" event_type="SAV" effect="Runtime behavior analysis is disabled because of a configuration error." mcs_id="ac8d4810-adb1-8fde-1b45-8e2f6882731b" cause="entityAppEvent" 2012:05:05-11:41:18 cats-kingdom epsecd[18350]: D Epsec::Utils::Logging::_log:59() => id="4211" severity="debug" sys="System" sub="epsecd" name="Acknowledging report(s)" reports="173471,205888" 2012:05:05-11:41:29 cats-kingdom epsecd[18350]: D Epsec::Utils::Logging::_log:59() => id="4207" severity="debug" sys="System" sub="epsecd" name="Recieved report(s) from Sophos LiveConnect" 2012:05:05-11:41:29 cats-kingdom epsecd[18350]: D Epsec::Utils::Logging::_log:59() => id="4230" severity="debug" sys="System" sub="epsecd" name="Updated ping information in the DB" mcs_id="ac8d4810-adb1-8fde-1b45-8e2f6882731b" 2012:05:05-11:41:29 cats-kingdom epsecd[18350]: D Epsec::Utils::Logging::_log:59() => id="4211" severity="debug" sys="System" sub="epsecd" name="Acknowledging report(s)" reports="173471"