Yep, sorry about that. This is a WordPress feature that I belatedly added to stay abreast of WP latest developments. When you create a menu you have the option of adding a description to each menu item, which then appears UNDER the menu item on your website.
The description can be found by clicking on ‘screen options’ in the menu section of Admin. The only thing then to do is to manually go to the menu item, find the description section and delete that long line of text.