Thanks for the replies.
Okay, by leaving <br class="clearBoth" /> in navigation display to stand, IE7 remains unaffected, FF still has the white space above the header_bg.jpg and IE6 has the white space to the right hand side. BUT, the additional images in the #navMain when there are products added to the cart now looks sane! So, leave navigation display alone then!?
Have removed float completely in #navCatTabs in main stylesheet.css so now there is no right float of the Category Tabs in IE7, IE6 or FF.
Agree could discuss colour choices but the white space showing below #navMainWrapper (or above header_bg.jpg) in FF remains a puzzle.



