In reply to Humphrey Allen:
Its banned. It's been banned for a while, but i've heard that in the last couple of years they now employ someone to check that no one bivvys between the tete rouse and gouter huts. Walkers also turned away during the day if they are headed up to the gouter hut without a reservation.
This is all gossip from friends who have done the route- i havnt been up it.