Some good wet foods imo:
Natures Menu - available from pets at home, small pet shops and used to be sold in Tesco but I have a feeling they've discontinued it now. 70% meat and no crap. It does contain a bit of cereal unfortunately and some sugar, but it's still a good food, imo, due to the high meat content and the fact that it's a complete food.
Hi Life. Available from PAH, most supermarkets, Wilkinsons. 60% meat. No grains. The poultry and meat pouches are not complete however, so need to be fed alongside a complete food. Hi Life Essentials are complete (available singly). They contain 50% meat with just the addition of tapioca, vitamins and minerals.
Natures Harvest. Available from PAH. Maybe smaller pet shops too but I've only seen it at PAH. 90% meat. Great food - ingredients: fresh chicken (90%), scottish salmon oil, cranberry, taurine, minerals and vitamins. It comes in foil trays and it tends to be difficult to spot on the shelf as there's only one flavour (chicken) and it tends to be stacked in a small box at the end of a display section.
Tesco Luxury - available from Tesco obviously! 50% meat. contains tapioca starch but no grains. Available in boxes of 12 pouches - they do a chicken selection and a fish selection.
Applaws/Almo nature - available from small pet stores or zooplus. organic, human grade meat. high meat content (70% I think). Shredded chicken (or fish) with a small amount of rice and cooking broth. Pretty much the same - almo nature is an italian brand whereas applaws is a UK brand. Almo nature does a bigger variety of flavours. It's a complementary food though, so can't be fed exclusively.
http://www.mpmproducts.co.uk/applaws_cat...
Bozita/Animonda Carny - available from zooplus. Good quality foods with a high meat content. Both do contain some by products, but european regulations regarding what can go into pet food are much stricter than those in the US (only meat from animals passed fit for human consumption is allowed to go into pet food) and they are named by products (eg chicken by product rather than the vague meat by product) so I don't have a problem with that since I don't feed them exclusively. They are both very economical.
I also feed
Cosma, Eagle Pack and Miamor from zooplus
http://www.zooplus.co.uk/shop/cats/canne...
There are probably a few more I've not mentioned. I tend to wander around the pet food aisle in supermarkets and pick up tins to read the ingredients. Sometimes I find foods that have a good meat content and low/no grains so will give them a try.