Have you thought of home cooking for Jazz ?
Lillys kitchen book is pretty good, You can change the recipe's to suit Jazz, you can get 2 percent turkey mince from sainsbury's and add the veg, the book outlines the benefits of most common veg, fruit etc,.
Bea was home cooked for about a year after her stay at RVC, her vet agreed that she looked good on it and the only reason I changed her to Kibble was that her Vitamin D and Phosforus needed to be constant due to her condition.
At least this way you will know exactly what is in the food, I stuck to the Loaf recipe, cooked a batch, sliced it and froze it, all I then had to do was remember to defrost it.
I used Spelt flour but you can do without it, the loaf will just be more crumbly when cooked so I would cook it in muffin tins so I didn't need to slice it.
Sharon.