1. A portable scanning device for scanning a product item, the product item having visible information relating thereto and a plurality of tags disposed thereon, each tag encoding data on an identity of the product item and the location of that tag on the product item, the scanning device comprising: a sensor for sensing the data encoded by at least one tag; and a processor for determining, from the sensed data, product identity data indicative of the identity of the product item and location data indicative of a location of said at least one tag on the product item.