Update to my post above.
I have now got CLS2SIM to connect to X-Plane after changing the IP on the Connections Settings page from localhost of 18.104.22.168 to the actual IP of the machine. (I did that in the past but there were probably multiple other settings wrong!)
I’ve started with Stefan’s Cessna 172 SP (CLSE-NG) from Profile Cloud.
Thanks Stefan, nice job and a good starting point for me to experiment with the various settings.