Yep - Asda is the easiest place to get them, the little tins are sold at Morrisons and Tesco, but not on the same deal as Asda, and the new Essential pouches I think are exclusive to Asda, at least I haven't found them anywhere else yet. Wilkinsons are allowed to sell some of the food, as are Co-op, but they tend to be the 4 tins of fishy food (and not all of those are complete).