In reply to Fredt:
I have camped there. You can find some reasonably flat ground near the hut, but in the valley not so much. Near the hut is probably your best bet if you want a tent with a large footprint.
You may see one or two other tents around but it's unlikely to be busy.
Bear in mind that when the weather is bad there it really mings.
Do you plan to carry it in or take one of the boats over from Elgol? In my experience the operators are quite accommodating.