I had already changed the theme Global CSS as you suggested and am not getting a visible icon.
As you can see from the screenshot, the css is in place but the icon is not showing. One strange thing I do notice is when I ‘Inspect’ in Chrome there is another area above the header highlighted in the top bar.
OK well it is now working… I think maybe my cache wasn’t cleared. There is another issue with WPBakery front end but I will create a new ticket for that if it has not already been addressed in these forums,