Thanks for your prompt reply, Ernest.
I’m using the WordPress Twenty Twenty-Two (child) theme which has Full Site Editing and doesn’t have widgets etc.
To save you some time, I have inserted the shortcode into the Nav Menu so that you can see the problem I’m having. See cancerireland.ie
Note, I previously changed the theme back to Twenty Twelve and inserted the shortcode directly into the menu (the old way – before Full Site Editing) but the results were exactly the same.
To access the Nav Bar, please
(a) click on Editor Beta (Image 01). This will take you to the Site Editor.
(b) click on the Nav Bar border and a + sign appears (Image 2). Click on the + sign to Add New Block (image 3)
(c) in the box that opens up, insert shortcode and click on submit (image 4)
Click Save (top right of page) TWICE to save the settings.
Now if you open cancerireland.ie in a new tab you should be able to see the problem.
I hope I’m making myself clear.
Best wishes,
Tommy