List not displaying correctly in IE

Hi all, not sure what's goin on here I'm guessing it'd really simple but sometimes can't see the wood for the trees.
Basically the thumbnail images are displaying ok in chrome but not in IE,it's only a list so i'm guessing it's a css issue somewhere.

http://www.ecswebdesign.co.uk/wip/childsplay/gallery.html

Any help would be much appreciated.