In reply to avonclimber:
Yeah, thats the entrance. I was back in Main Area over the weekend and the sign was there, it was just on the floor. I propped it up against the railings, but didnt have anything to tie it on with.
It might also be worth putting a few more up because there were a pair of climbers on Depravity (i think - it was definitely in the restricted area anyway) on Saturday. I guess if you head straight towards the left hand end of the restricted area then you might miss the signs.