I have placed the default code into my 'Header' and thus have passed Googles 'Mobile Friendly' test! on all my pages!!!
But, although the 'viewport meta tag' is working one main-site ; it is not working on any of the multi-sites!
This is also the case on several different sites that I have!
Perhaps this is a similar phenomena to 'plugins' that need that 'little extra' before they will work on multi-site?
Any suggestions, please?