woocommerce shopping cart double add

I have a problem (must be with the javascript) on my shop.
I go to this page and select Add to Cart on one of the items: https://www.proxyplayer.co.uk/NewSite/?page_id=4
It gets added as 1 item into the shopping cart on the right sidebar. I then click View Cart but as soon as the checkout page appears it is suddenly 2 items

I tried looking through firebug and found that there is a blank background-image: url()
which causes a double submission.
ANy ideas how I can fix this?

/* Background */
#show-space,
#inner-page-show-space {
background-color: #ff9f12;
background-image: url();
}