[2011] Centralize horizontal submenu under its parent

Hello,

The website I’m working on is
https://51stokescroft.com.gridhosted.co.uk/

I’m stuck on how to centralize the submenu under the parent menu item.. I managed to do it with the submenu on Party Bookings by adding

#menu-item-59 {
  padding-left: 2.2em;
}

…but can’t seem to be able to do the same with the other submenus?

I was also wondering if there’s a way to display the submenu when I’m on it’s parent’s page?

Thanks a lot, help will be muchly appreciated! ??
Domi