Psssst!!
How about this - it seemed to be recommended on some uk forums?
You'd have to research the ingredients of course as it only states 17% protein.
Or this at 18%?
Basically look at all the commercial diets you can and compare it to the profile of the food you want to use.
The hardest part might be finding a farm supply outlet near where you live. Find the one thats easiest to get to then look at the makeup of their feed.
dr del