Thanks Mohamed - very helpful. I took up your ideas and looked at the code using Firebug in Firebox. I found that the classes for the Image , Name unit Price etc namely
hikashop_cart_product_price_title,hikashop_cart_product_name_title, hikashop_cart_product_quantity_title , hikashop_cart_product_total_title, hikashop_cart_product_image_title were not defined in the css.
I seearched on my download file and they weren't there either. When I defined the classes the layout lined up perfectly. Somehow Safari and Fiurefox must do this intuitively! Hope this helps someone else.