I turned up as directed - but there was no guide and no tour. Waited over 30 minutes then gave it up as a bad job! I suspect the tour was cancelled due to lack of bookings, only no-one let me know (and I was still getting reminders from TripAdvisor 2 hours before it was due to start). Meet up point was over 30 minute walk from my hotel so all in all I lost a good hour and a half which I could have spent doing something else. Still waiting to see if the money will be debited from my account... Take note TripAdvisor, operators promoted by you should be validated as authentic and genuine - not time wasters or scams.