It's 25% off the range, from what I can see from the Manc Arndale.
Best Buy for me is the Wilko's own 2 can Beer range at £12.75 - Golden / Real / Best. I think it would be hard to get unhopped LME below this price, let alone a "no adds" kit. Having said that, I would still do them to 25L with 500g of sugar, because my taste is for a slightly lighter beer than most experienced drinkers.
Wherry at £14.25 is a more or less guarantee of a great drink - in 12 weeks time - and provided you follow the cleansing routines outlined elsewhere on the site.