Went into my local Big Johns (B'ham, Erd) and saw these amazing offers on the Cheese Burgers. They have the Single for £0.99 and the double for £1.69 and the triple for £1.99, and the meat pieces are very chunky also, I had trouble finishing the triple cheese burger.
Done a quick search, couldnt see it anywhere on the site, so I posted. The direct link doesnt take you to the Special Offer page. You'll have to find it yourself, thats how the site works.