White Space Above Header

Hi,
Hope someone can help me.
My site looks fine in IEv8 compatibility view, however if viewed without compatibilty view, in FireFox & Safari I get the dreaded white bar above the header & the Home, Log In & Search buttons are mis-aligned.
Can anyone please tell me what changes I need to make in the stylesheet so that there's no bar or mis-alignment whichever browser I use?
I'm running version 1.3.9h
https://www.BlackburnModels.com

Many thanks in advance

You have apparently attempted to delete the tagline, but left the <h1> tags in the define. Since the define is not empty
if (HEADER_SALES_TEXT != '') {
a blank <h1> is output which takes up space.

Many thanks for your quick reply.
When I "View Source" I can see the bit you are referring to, but I can't figure out how to edit it!
I've been looking in /includes/templates/mytemplate/css/stylesheet.css.
Where should I be looking?
Thanks again,
Chris

In a language file which has statements like
define('WHAT_EVER', 'What ever');

Use Tools > Developers Toolkit to search for HEADER_SALES_TEXT and see where it is defined.

Many thanks for your help.
I've got rid of the white space, just need to work on my mis-aligned elements now!
Thanks again,
Chris