How do I change the colour of the top menu links?

Have you tried:

#access a {

}

?

Wont that change the colours of the other two menu nav bars, the main menu and footer menu?

Try it and find out

Hmmm it changed the colour of the main navigation bar but it didn’t affect the footer menu or the top nav bar menu.

It’s the top nav bar in the top right hand corner that I want to change colour.

Oh try this instead:

#menu-top-menu a

Thank you so much, that worked a treat ??

#menu-top-menu a {
     color: #F7DD00;
     font-size: 22px;
}
#menu-top-menu a:hover {
     color: #FFFFFF;
     font-size: 22px;
}

The CSS tags for customizing the main menu are listed in the theme FAQs.