I think this is probably including unsalted roasted whole peanuts in the shell. They are pretty cheap to buy in big bulk bags. If you want pre-shelled roasted, salted, or seasoned peanuts, you will pay extra for it.
Unsalted in the shell is what I was talking about, I guess its a regional thing. The UK isn't even close to anywhere they can grow so they're really expensive here.
This is US, but just in awe you were wondering what the difference is for us. I'm actually pretty shocked the prices are so close together no matter the form.
Peanuts are cheap in the US. There's always peanut butter too, which despite the processing required is probably even cheaper, maybe because of shelf stability and packing density.