Items going in cart and then not appearing

Hi this is causining me major problems as I am about to go live.

Products get added to the cart, but then the page will not go to the checkout page and I get listings instead.

Or the products do not get added to the cart.

http://workwearandsports.co.uk/index.php?option=com_hikashop&ctrl=category&task=listing&cid=811&name=mens-sportswear&Itemid=170

Thanks

Nav

It seems to be this plugin causing the problem.
Disabling it caused all to be okay.

System - EU e-Privacy Directive

I'll speak to the developer and report back