or go to one of their large number of stores and save a pound. https://www.grapetree.co.uk/store-locator/
... well, in Lidl walnuts are £10/kg (£1.99/200g), but there is no delivery charge, so one would have to but at least 5kg from this seller to break even.
I'm not aware of this quality of nut being anywhere cheaper in general. Doesn't work as an online deal unless you're buying a lot more, but they have a lot of stores. Elsewhere £5 or more for 400g is more usual.
Why is this posted as a hot deal? It appears to be the regular price for a common product.
I only eat these if they're on top of a walnut whip.