www.wysiwygwebbuilder.com

I realise this is probably straightforward, but I just cannot find how to increase the space between the sub menu items. I have looked at HELP but it doesn't cover that, just says you can change style.

Padding?

That just makes the boxes bigger, I need to separate or widen the space between the boxes for ease of selection on mobile pages

You cannot add spacing between the items because then moving the mouse in between the items would close the menu.
Padding can be used to make the items bigger for mobile devices.