Well, a big UP to the Conrad for acting on my email. Just had a fifteen minute call from Gee (?) the front of office manager, explaing what happened, from the hotel's point of view, having reviewed the calls made to and from my daughter, the CCTV footage of her going to the concierge etc. etc.
It seems that becuase of low occupancy, every effort was made to offer Diamond member benefits to my daughter, but that there were communication issues, in things being misheard or misinterpreted on both sides.
All in all, I am alot happier, but my daughter still feels that she was made to feel unwelcome, and that will remain her opinion of the Conrad. I will be in Bangkok in a month or so, so will go and see the manager, even if I don't stay there myself.