menu widget :Before element on first item

I have a child theme and have added a three column flexbox footer with widgets to the Charm theme. One of the columns contains two widgets, a text widget and a two item horizontal menu widget.
The CSS, which is borrowed from the main navigation menu style for the original theme, uses the before pseudo element to remove the bullet style from before the first emun item. However WordPress is generating the before pseudo item on each of the menu items in my mew menu widget, meaning that the bullet style is being applied to both items in my menu rather than just the second item.

How can I ensure that the Before pseudo element is only being applied to the second menu item?

This is the most complex custom wordpress coding that I’ve done, so any help would be really appreciated.