Weird top margin problem in repeat region

Hey all, My repeat region looks fine in all browsers except IE7. For some reason the 5th product onwards seems to have a bigger top margin (about 20px), which pushes the columns down. My code is valid and I've checked CSS and stray DIVs etc. I really don't get it as if the problem was with the repeated container DIV, surely it would affect every DIV? Can anyone shed any light? Here's the page and a snapshot below of the problem. thanks http://goo.gl/5rlgc