It was very simple. The Air Theme had the Discourse Search Banner installed as part if the complete theme.
As stated running Test-Passed.
Once the Chat Plugin is enabled the Wrlcome banner if the Discourse Search Banner no longer displays the Welcome message.
Turn Chat plugin off. The Welcome banner is displayed.
Chat plugin Disabled
You can see in this ss the Chat plugin icon is gone from the header. You can also see tge other effects that the chat plugin is sermingly doing to the background creating a white empty rectangle ignoring the blue background.
Now looking at it might it be interfering with Air Thene’s blue wallpaper? as text is white in the banner. So I might be on the wrong track with the Discourse Search banner. It might be a conflict with part of the Air theme… ??