I'm looking to get one of those turtleneck jumpers for the winter months, but I'm not really sure where to find them. I've searched a couple of sites i.e. Next, Topman, River Island, but haven't found anything. I'll be heading into the city tomorrow, so I'll be shopping around Oxford Street etc. So does anyone know where to find these jumpers? Below is an example of what I'm after.
The black or white ones are what I'm looking for, so anyone have any ideas?

The black or white ones are what I'm looking for, so anyone have any ideas?