Timberwolf organics
http://www.zooplus.co.uk/shop/dogs/dry_dog_food/timberwolf it's £37.50 for a 15k bag,but it is well worth the couple of extra ££.
The reason your dog probably has the dry coat is because of the low protein and fat in Burns.High protein doesnt automatically equal weight gain,you do however have to feed less of the high protein foods(as long as the protein is derived from meat and not corn or corn gluten meal) as they are more nutritionally dense.
Timberwolf do both low and high protein/fat foods,the 'black forest'(venison) being the lowest at 22%P and 12%F,with the highest being wild & natural(what i feed) at 36%P and 18%F.Many a dog has lost fat and gained better muscle tone on the W&N,as it is grain free,alot of dogs turn carbs from grains straight into fat..... I have seen a huge improvement in my dogs overall health since feeding TO,coat,skin,energy levels etc,and it's only been a few weeks.I thought they were doing well before,but obviously there's always room for improvement :D