You are in the U.K., right? You have access to different foods than most of us though we do have some U.K. members who may chime in. But anyway, you may be able to return the unused cans, if it's cans. That stuff is expensive, no need to use it all up if you don't need it. I haven't needed that food for my dog but when a young cat needed it once he recovered I was told to look for low ash food. Not low protein. That was a long time ago, maybe most foods are lower in ash than they were and it is more of a problem in cats, especially males, I think.
I had an older cat on it too and her problem never resolved completely and I was never able to take her off the special food. She had Cholangial Hepatitis for which there was no cure, only maintenance. Of course I forget now what it was but there is some crystal fighting ingredient in that food than no commercial foods here had in them in nearly the same amount. I think you need to discuss with your Vet whether your dog is young and completely recovered or if there is an underlying condition you will need to target all her life. And, your Vet should be able to tell you what to look for, or watch out for, in your new food.
For information on food ingredients in general I do like The Dog Food Project - How does your Dog Food Brand compare?. It helped me understand what are bad, good or ingredients that are only bad if there is too much of them in the food. It's based in N. America so some of it won't apply to you but basic ingredient knowledge can only help. Good luck, glad she is better. And welcome.
P.S. the bold blue is a link to the site.