Okay, I’ve had an email back from Corona last night saying there was a problem with their build server that was causing the issue.
This morning, I’ve rebuilt one of my Android and iOS apps, installed it on a device, tested the app on the device, and everything appeared to run correctly.
Simon
PS - the only issue I did have was, the first time I ran the simulator to create the build, it complained the plug in was missing. Killing and restarting the simulator fixed eliminated the problem.