Other Box Offices don't seem to be getting any at all so the Mean Fiddler/Astoria are peoples best bet. I don't know how limited/allocated they are but I believe it's two per person and they really don't have all that many at all.
I would be amazed if I can get some (....remembers the fiasco when the Poppies were selling their tickets through the fan club to start with.....) and I'd be even more amazed if I can get any quantity for either night so if you want tickets please try and get them yourselves (especially if they are limiting it to 2 or 4 per person). If I can get more I will, but at the moment if I can get one ticket I'll be happy.