Prestashop Expert Needed

I have an site running prestashop that needs altering to be able to accept drop downs in the additional fields for certain products, however its already been heavily modified for other things so youll have to start with already modified code.
The site is thecufflinkstore.co.uk, you can see the current status of the modifications at test.thecufflinkstore.co.uk. Although the dropdown has been added in to certain engraved cufflinks, it is not stored in the cart and also throws a parseerror when adding to cart.