Bargain Buy 2 get 1 free fertilizers at Wickes

Westland 3.5 Kg Packs of Blood, fish and bone, Bonemeal and Growmore £4.49 each had signs instore "buy 2 get 1 free", reducing it to 86p/Kg.

I don't see this offer on their website, and there was no reduction when I tried adding3 packs to my basket.

I'm after some cheap Growmore as Wilkos (£1.17/Kg) never reduced theirs last year, but somebody had bought every single pack from both displays in the Wickes I visited.