[andygrif]

You are asking for something that doesn't exist, which is proably why she didn't know about it.

Sky are planning to do some sort of pseudo video on demand with the reserved space on some Sky + boxes, where they will record stuff when you're not watching it into a separate part of the box that you can watch or not whichever you like.

But it's not there yet, they've just rolled it out to Sky HD boxes and only some Sky+ boxes have the required specs to handle it.