I've been waiting at the entrance of Plaza Del Carmen for around half an hour since 19:00 ,and nothing.Then, 10 mins later i've met a kind british( i guess?) man who was also waiting for the meeting.But well, considered you were waiting for us in a wrong place, there's no problem at all. By the way, for the next meeting, (if there's going to be a next one), I suggest another more quietly place, if you get what i mean..something as san telmo downtown, maybe?? ..i've never been at Plaza Del Carmen,but it seems like an over populous zone...one thing to say: seconds after i reached the place, a bunch of poor people came over me and the started bullying and asking for money again and again.....hmmm, well, just a suggestion.Good luck with the next meeting anyways .