Hi again Steve and Sonya,
Arginonta Valley: The access has been sorted between the municipality and the shepherd claiming the land, BUT a proper gate has yet to be installed. It is long overdue but hopefully it will be installed any day now. So until then, the hole in the fence is still the way to approach the crag.
Greece guidebook: Yes, there will be an updated edition this winter (ETA around late November/early December 2016). We are currently working on it. However, Santorini will not be in this edition either (sorry). That said, the climbing info on Santorini can be accessed online here (it is in Greek, but you will have no trouble figuring out the photo-topos, grades and lengths): http://www.vrahomania.gr/σαντορίνη/
Naxos: There is only bouldering that we are aware of, but no bolted routes. I don’t think there is any info online, but I will look into it and let you know if I find anything.
Climbgreece.com posts: We have not deleted anything; we will only ever delete a post if it is offensive. I believe you are referring to the posts below?
http://climbgreece.com/forums/topic/santorini-climbing/
http://climbgreece.com/forums/topic/sector-anatoli-nafplio/
I think I answered all your questions. If not, let me know!
Best,
Katie (on behalf of Aris)