just a thought, perhaps 'No Hijacking Threads' and what is meant by that should be added to the group rules, together with a 3rd question, asking if people understand. Otherwise infrequent users may be unaware. Apologies if i've just hijacked a thread...
FYI, not surprisingly, Chaengwattana was very busy when I arrived without an appointment on Tuesday, at 10 am. The queue to get through the entrance was 30 mins. I was given ticket 74, they were serving no'44 when I sat down. They got to 70 when they stopped for lunch at 12. Finally left at 1:30 pm. I would certainly advise making a prior appointment