Nav bar showing sub pages – want to hide them

I have a site using the theme Alpha by ChiQ

My problem is that the top nav is picking up my subpages and showing them, is there a way i can hide or exclude these pages from being displayed but sit access them through a link in one of the parent pages?

My old theme Fancy did this fine but since i have swoped this doesnt seem to work?

from what i can tell the code that is picking this up is

<?php dp_list_categories(); ?>

if anyone would like to look my site is https://www.eventindustrynews.co.uk