As I said I haven't, as yet, been able to view the site on a Mac. The problem showed up on a PC on Safari, Chrome & Opera.
That problem is a clear border (or gap) appearing between the "Baba News" button and the dropdown "News Item" button.
It's strange that it only happens on that specific part of the menu. I have checked my HTML but cannot see a cause. Could be a CSS or Java Script problem...
Thank you for your response.