Hi Dan
A mate of mine goes to a part of the dam called Grabine (?? spelling) and a couple that I know just had their wedding out there so I think there are a few facilities there that would suit your needs, might be worth a thought.
Quart pot is another part of the dam but I don't know if is is a camping spot or just a fishing place
The main camp ground near the wall end of the dam has all facilities although last time that I was there the little shop was not operating due to the lack of water (5%) and customers, mabe it is better now with more water around.
Happy camping,
Trevor