I've created a minimal test case to enable someone better at CSS than I am, to more easily see what's going on.
Page;
http://username132.tasminslair.com/m...es/welcome.php
CSS;
http://username132.tasminslair.com/m...sheets/all.css
Menus;
http://username132.tasminslair.com/min_test_case/menus (there are three involved).

The problems are;
a) primary_nav is squashed over to the left in IE, considering it is supposed to have a min-width or width of 85% - removing the home_image CSS causes it to shoot into the middle fo the page, although it doesn't actually get any wider
b) secondary_nav and tertiary_nav (the submenus on the left) are really wide in IE despite width: 25px; specification
c) secondary_nav and tertiary_nav are displaced about 80px to the right in IE and Opera, despite their absolute positioning

Thanks for any help or general advice offered.
[The actual site I'm working on, http://username132.tasminslair.com/w...r_officers.php looks fine (apart from footer problem) in firefox but is really messed up in IE.
If I change positioning to float and add margins, then I have to give different margins to FF/Moz and IE to get the right positioning but I've heard it's a bad idea to use different styleshets for different browsers]