Attitude header in Internet Explorer 10

Hi, I am using the Attitude theme and have a child theme activated.

Can someone help me as I am at a loss at the moment and really need to fix a problem with the header of my dev website when viewed with Internet Explorer v10. We are supposed to be going live this evening and I can’t get it to display correctly in IE.

I have removed the spacing above the header using css and it displays fine on Chrome and Firefox browsers but not Internet Explorer v.10 where it displays really badly. On IE the header overlays the nav bar and the menu items shift to the left into the background.

Do I need to do something specifically for IE when removing the spacing?

I have used the following CSS

/*** Header ***/
#branding {
    margin-top: 10px;
}
/* Remove the heading group padding */
.hgroup-wrap {
    padding-bottom: 0;
    padding-top: 0;
}
.hgroup-right {
margin-top: 0px;
}
/* Remove the logo margin */
#site-logo {
    margin-top: 1px;
}

Please advise.

https://www.ads-software.com/support/theme/attitude