I've said it elsewhere but, generally speaking, if they are Thai and they are using a name, they are probably genuine. I have seen one or two recently which fit that criteria but which I suspect might be fake but most of the time it works. Also, the more photos they have the more likely to be genuine, especially if you recognise the style of set for the photos which are sometimes used again with different girls.
What Nervous J said is pretty much correct. For example, if you search for Asian female escorts in Nottingham, the following either are or probably are genuine ( in terms of the girl in the picture is the girl you will see ): Kate Thai, A_Eva, Nutty, Hot and spicy Thai Emma, Meena, August, Gina, and Mami Meya.
"Thailand duo sweet. Asian" and "Asain Thailand Sexy Beauties" ( and the incorrect spelling of 'Asian' is from their ad ) are advertising Thai girls but neither use a name and both only have a couple of pics. They appear on the first page of search results and along with almost every other ad on the first page are ads with girls who are not the girl(s) you will see.
Kk Chinese massage I think is an outfit which has been regularly reviewed here. I think the girl in the pic may well be who you will see but I am not sure.