After trying unsuccessfully to compile an app, I realised that my Xcode was missing the iOS 18.2 Platform, so 8GB and about 5 hours later (yes Samoan 4G Internet is slow) I installed the Platform, restarted Xcode and the Simulator, compiled my test App and viola! It is working both on the Simulator and to my iPhone connected to the Configurator.
If this old hack of a programmer can make it all work, anyone can. My Macbook dev environment is now seamless in its operation, with no more rebooting into Windows when I needed B4x.
Cheers,
Kev