If you want to go down the raw route, Natural Instinct do a complete frozen cat food in several varieties. I use them for the dogs sometimes, they think they are super yummy.
I fed our cat part DIY raw (he wouldn't fully transition, but loved minced beef, fish and chicken wings) and Classic or Sainsbury's own brand canned food. Both of these are free from cereals, unlike a lot of the more expensive brands such as Whiskas.
If I needed to feed a dry food (I prefer wet for cats, especially male ones) I used Fish 4 Cats, but I don't know if they have since changed the formula, the dog version has a lot less fish and a lot more carbs than it used to. It didn't have cereals or artificial additives. They also do pouches of salmon mousse that our cat loved, that were just salmon and seaweed extract.