Chris I'm no expert as newbie to all this VW madness, but I think Crank position sensor, crank sensor, engine speed sensor are all different names for same thing!
I phoned Europarts today, asked for it by a couple of names and the guys there said it was the same thing.
Price was £52 + vat, if you find them elsewhere cheaper post on here as I am trying to save myself cash.
Hope that helps, but as I said there are fair more clued up bods on here!
Good luck mate