Thanks, Ok well the padding-right was already set to 6px. However, I changed the width:320px to 300px and that moved the "last" on to the correct line. So that's that bit solved.
Now to figure out this white square with the red cross in IE.
EDIT: Of course... i've just figured it out.... there's supposed to be an image there "arrowdown.png" but the link to it isn't right. That's why IE shows the red cross and FF shows nothing.... silly me.
EDIT 2: Fixed.

Now there's only the IE 8 Compatability View problem, but I can live with that for now.