Keyboard missing a key

So I got a new keyboard; this one's a cool USB one. Trouble is: it has too many shift keys. By which I mean, to the left of the Z key, where there should be a symbol key, there's a shift. (This has US keycaps, but I type with UK bindings, hence it should be effectively a backslash/pipe.) Anyone know if I can remap this additional shift to be backslash and pipe; if I can't do that, anyone know if I can remap the Windows key to be that?

Before anyone tells me I should have looked at it before I bought it, it was a gift, okay?