KFC is the only one I know out of those three but they don't have the best chicken either. I prefer Morleys though. Anyone from London would most likely have heard of Morleys
I've had both Churches and Popeyes within the last 3 weeks and both were horrible. Not only were both orders messed up but the chicken was bad at Churches and the biscuits were bad at Popeyes. Popeyes coleslaw was bad and their fries came under my chicken and were so soaked with grease they were soggy.
I haven't had KFC since before 2006 (I signed a P!nk led petition to "Kick The Bucket" against animal cruelty) but their chicken was good at the time and their coleslaw remains the best.