Skinners isnt too bad for its price. First ingredient is rice, but i dont think you are going to find a great food at the price you wish to pay. I know many dogs do well on this one..
Skinners Petfoods - Field & Trial Duck & Rice Hypoallergenic Dog Food
Arden Grange is another good one. You can buy either 30kg with free delivery on eBay for around £50 (free delivery and you'd have to do a search). Or you can get it from Berriewoods for £26 pounds.
Berriewood Wholesale - Arden Grange Adult Lamb & Rice 15kg(Breeder Bag)
I think Bakers is stupid expensive for the quality. I remember when it was about £12.50 a sack.