I’ve added the new piece of code but it’s still causing problems. Here’s all the code in the CSS:

.sub_menu { font-size: 16px; } /* changes the font size of sub menu */
.fixed_header.social_header #main { padding-top: 174px; }
.main_menu ul:first-child > li > a { line-height: 190px !important; }
#header .mega_menu_title { #0e2f61; }

.title_container { background: url(http://www.test.theimplantcentre.com/wp-content/uploads/2014/02/Crumbsbanner41.jpg); }

.avia-heading-row {
color: white;
}
.price-top-margin {
margin-top: 37px;
}

tr th:first-child, tr td:first-child {
vertical-align: top;
}
.main_color tr.avia-heading-row {
background: #2f5691;
}
#header_main, .header_color .main_menu .menu ul li a { background-color: white; }

#header_main, .header_color .main_menu .menu ul li a { background-color: white; }

.tab_titles div {
font-size: 14px !important;
}
.avia_mega_div, .avia_mega_div .sub-menu {
background: white !important;

@media only screen and (min-width: 1140px) {
#top #header .avia_mega_div > .sub-menu > li > ul > li a {
height: 40px !important;
line-height: 25px !important;
}}

#header_main .container, .main_menu ul:first-child > li > a {
height: 143px !important;
line-height: 190px !important;
-webkit-transition: all linear 0.2s;
-moz-transiton: all linear 0.2s;
transition: all linear 0.2s;
}

.header-scrolled #header_main .container, .header-scrolled #avia-menu > li > a {
height: 80px !important;
line-height: 80px !important;
}
#header_main img, #header_main .logo, #header_main .logo a{
width: 252px !important;
height: auto !important;
max-height: none !important;
max-width: none !important;

-webkit-transition: all linear 0.2s;
-moz-transiton: all linear 0.2s;
transition: all linear 0.2s;
}
.header-scrolled #header_main img, .header-scrolled #header_main .logo, .header-scrolled #header_main .logo a{
width: 126px !important;
height: auto !important;
}
.avia-content-slider .slide-entry-title {
display: none;
}
#main > div.main_color.container_wrap.fullsize > div > main > div > div > div.flex_column.av_one_half.avia-builder-el-11.el_after_av_one_half.avia-builder-el-last.column-top-margin {
margin-top: -8px;
}
#av_section_1 > div > div > div > div > div.flex_column.av_one_fourth.first.avia-builder-el-13.el_before_av_three_fourth.avia-builder-el-first > section {
margin-top: 20px;
}

.page-id-75 .avia-section-small .content {
padding-top: 0;
}

.header_color .avia-tt { background-color: white; }
.header_color .ajax_search_image { color: white; }

.header-scrolled .main_menu ul:first-child > li > a { line-height: 58px !important; }

Thanks, but I’m not sure it’s doing what it’s supposed to do. There’s a strange blue strip plus the menus doing strange things; some are staying put when scrolling, they are still running over the logo etc.

That’s fixed it, many thanks

Thanks Josue that’s resolved the background colour issue but it’s brought back and old issue with the ‘Why choose us’ dropdown menu, see #225238 (Header adjustments) from Yigit. The dropdown works ok when at the top of the page, but when using it half way down the page the sub menu headings are all spaced out http://www.test.theimplantcentre.com/wp-content/uploads/2014/03/Screen-Shot-2014-03-05-at-08.27.34.png

Many thanks Ismael, somehow I’ve changed the main header and dropdown to have a blue background! How do I change them back to white?

doh! that’s makes sense thanks

That seems to have sorted it many thanks for your help.

That’s great many thanks

Still not right I’m afraid…
http://www.test.theimplantcentre.com/wp-content/uploads/2014/02/Screen-Shot-2014-02-17-at-19.40.58.png

Sorted, many thanks Josue