You can order Eden via their website. Be aware that if you order, say, 6kg, it might come in one bag, so you'd have to have a storage solution ready.
I alternate Fish 4dogs with Eden for Millie. However she voted with her teeth last week! The two bags of food were stored where I thought she couldn't get to them, with Eden the newest in reserve at the bottom. I thought the rearranging of her bed was very loud, when in fact it was her tearing the Eden bag open! Fortunately I had still to give her breakfast that day and so it was slightly less than usual.
Poos with fish4dogs are smallish and firm; we're in the changeover phase now and haven't noticed any difference with substitution of some Eden.
Her coat looks fine and she's lost the hyperactivity that she first had on arrival with bags and bags of Bakers!
Hope you manage to find suitable food for Diesel.