Found in bexleyheath, London poundworld on the square it was labelled as manager special. When asked i was told it was nationwide deal, so I would suggest calling before you go to your nearest poundworld.
I am aware Costco and various other bulk buying stores usually do deals such as 2 of these packs for £10.
But I don't drive nor have a Costco near me so this deal applies for people like myself.
I did do a price comparison and it stated bag Asda are matching the price but they aren't available online so maybe in store ?
Tesco is next selling for £9