This code altering the border colours as the member above said, as really worked, thanks! I changed mine to match with my maroon and orange menu theme.
}
.navigation-main ul > .current_page_item a:after,
.navigation-main ul > .current-menu-item a:after,
.navigation-main ul > .current-post-ancestor a:after,
.navigation-main ul > .current-menu-parent a:after,
.navigation-main ul > .current-post-parent a:after {
content: '';
font-size: 0px;
line-height: 0%;
width: 0px;
border-top: 6px solid #5E1818;
border-left: 6px solid transparent;
border-right: 6px solid transparent;
position: absolute;
bottom: -6px;
left: 50%;
margin-left: -6px;
z-index: 9995;
}
.navigation-main ul > .current_page_item:hover a:after,
.navigation-main ul > .current-menu-item:hover a:after,
.navigation-main ul > .current-post-ancestor:hover a:after,
.navigation-main ul > .current-menu-ancestor:hover a:after,
.navigation-main ul > .current-menu-parent:hover a:after,
.navigation-main ul > .current-post-parent:hover a:after {
border-top-color: #C46129;
}