I still don't know why this happened but I have managed to get everything
working again.
The solution was to go into 'systemsettings' and delete every printer before
then re-running thr GoogleCloudPrint import routine
/usr/share/cloudprint-cups/setupcloudprint.py
After doing this all printers
I've rebooted my server for the first time in ages and now my Google Cloud
print server has stopped working.
If I start up the server in a terminal window I get the following (I also get
this if I "systemctl status googleCloudPrint"
[gary@lou
~]$ /usr/bin/google-chrome --type=service --enable