On the basis of a post last week I have tried out Tails.com food.
Apologies to the poster whose code I used I lost the post.
Here are my codes if anyone wants to try.
Free month of Dog food from Tails.com
Codes POPZY5SAB
POPSRS76A
POPF7X4AV
POPD8YLPT
Delivery £1 slightly more if offshore GB