Just had this leaflet through the door. It's due to start on the 17th, although keep an eye out tomorrow too. My local have had them out on the offer a day early before. So if you're there anyway it may save you a trip on the 17th if you fancy this one. Ends the 6th September.
Also Co-op offer free del with min spends when shopping in store? It's not available everywhere just yet but worth a look it you're on foot - See link in comment #1 for more info on that.
Site not updated with the info yet but still... This is what you get for your £5
SFC Take Home Boneless Box - 550g
Onion Rings - 454g
American Fries - 750g
Mini Corn on the cob - 625g
Magnum Classic x 4 - 440ml