I've been checking my site in compatibility mode today and it's proving to be a bit of a headache as i can't seem to pinpoint the source of my problems using Firebug. Please, can anyone with some more experience of CSS take a look at my site in compatibility mode and/or cross browser views?

In IE7 I am getting this. Circled you can see a strange staggered effect between the left nav headers and the centre .h2 header.... this only happens in IE7. Also, only in IE7 I am having a strande left alignment on the manufacturers list:


Then, in Safari, Chrome and Opera, I am getting this where my languages widget/flags are pushed up and off the top of the screen slightly. Also in these browsers, there's a strange white horizontal line that I can't seem to find the source of:


I've been trying for hours to sort these issues out using trial and error and a very limited knowledge of CSS. Please, any help from the forum will be hugely appreciated...