Don't know if anyone feeds it but Zooplus have offer on Harringtons - buy one get second half price.

https://www.zooplus.co.uk/shop/dogs/dry_dog_food/harringtons/961733?unique=HTML85

Looks like a good opportunity BUT after switching my Whippet onto their Grain Free Salmon, and also Chicken when I lost Frankie, she eats so little it would take far too long for her to get through a 15 KG bag so there's no point my buying anything other than 2 kg bags, which I can buy in Morrisons for very little!!