cart subtotal display incorrect by a pence

for somereason my cart subtotal is incorrect.. add on a couple of pence for some reason.

Total Items: 1 Weight: 20kgs Amount: £53.99

              Qty.                   Item Name         Unit         Total                                         


                            [\[IMG\]http://www.rubberduckbathrooms.co.uk/store/bmz\_cache/5/528bd20c708f277a1f1c612ea173d12a.image.50x36.jpg\[/IMG\]Wedi  Tilebacker Board 2500 x 600](http://www.rubberduckbathrooms.co.uk/store/index.php?main_page=product_info&products_id=2374:412e6a79614403501860233d547c8af1) 

• Thickness - 20mm

           £53.98        £53.98                    [\[IMG\]http://www.rubberduckbathrooms.co.uk/store/includes/templates/template\_default/images/icons/small\_delete.gif\[/IMG\]](http://www.rubberduckbathrooms.co.uk/store/index.php?main_page=shopping_cart&action=remove_product&product_id=2374:412e6a79614403501860233d547c8af1)                                Sub-Total:  £53.99
  

Shipping: £19.99
Total: £73.98

anyone have any ideas???

switched the tmp_shoppingcar_delfault back to an original to make sure the the cross sell or shipping rate in cart wasn't to blame and the price is still the incorrect price.

looking in moire detail the sub total is correct its the total in that cart that wront... the unit price is 53.99 not 53.98