I found this deal at Game Kingston today.
Normal Price £20. With Game Deal of the Week youo get the Quick Charge kit for £15 when you buy any other item. I bought a pre-owned Pro Evo 4 for the PS2 for £0.98 and got the Quick Charge Kit for £15.
I'm not sure whether this promotion is nationwide but I suspect it won't last long as it's called Deal of the Week.