TD,
Its the par 4 6th hole. It used to play as a short par 4, about 350ish, maybe a bit more, off the top of my head, but to lengthen it would mean going back onto the East course, so there is a tee at about 420 built on the East (or it might be a regular one from the East?), but for everyday play there is a hedge that is wheeled across to hide it.
Cheers,
James