I’m so sorry, I was sure I’d let you know that I’d solved this. Maybe I wasn’t logged in at the time. Anyway, the problem was essentially that I didn’t know how to use the Inspector in chrome properly to show my the hover code. Once I found out how to do that, I was able to edit the CSS. For the benefit of anyone else having the same problem, the code I used was:
.not-front-page .header-wrapper .menu li a:hover {
color: #663300 !important;
}
Thanks for responding anyway. The site in question is still under development so I couln’t provide you with the URL.