I'm not familiar with UK cat food, but in general pouches are generally not a very economic way of feeding. Usually you can get better value if you go with canned food.
A really cheap-and-dirty way to evaluate cat food is to look at the first 3 or 4 ingredients that they list, and compare them. Meat is best, meat meal is next best, grains, fruits, vegetables and by-products are worst.
You can get a much more thorough discussion of this here:
http://www.littlebigcat.com/nutrition/s ... -pet-food/Purina has a lot of different formulations, but in general they tend to be about bottom of the barrel nutritionally imo. Just because your female kitten doesn't like that particular Purina mix doesn't mean she doesn't like dry food. She might just have more discerning tastes :) I've found it usually takes trying 3-4 types of food (brands/flavors) to find 1 that they really love, but it's worth the effort in the long run, and it's also good to find several that they really love (and are good nutritionally of course). Definitely be prepared to throw out food that they don't like. It just doesn't make sense to feed cats (and especially kittens) food that you know they don't like.