If you are looking for some premium escort girls in London I really don't know what to say, as there are a lot of places and websites where you can find what you are searching for and I don't know what to recommend, but what I can tell you for sure is that it is worthwhile to check the London escorts on the agencies websites, as there are a lot of them on the internet and they are always offering pretty decent info regarding all the girls.
So... I don't know if you have searched on Google but I am pretty sure that this is the best ideea that you could apply in this type of search, as there are no actual other legal ways to seing an escort, but through the phone or the internet connection due to a couple of British laws that interdicted the presence of girls of streets.
So now, basically all the escorting in England or to be more precise in London is controlled by the escort agencies that are having a couple of girls (in fact some of those agencies are quite big) that provide a wide range of services.
As far as premium escorts go, everyone should be really careful when reading the description of a certain escort, as in fact all of them are presented in a very nice way, and all of them have nice pictures, that have been edited in a way or another.
So, finding some premium escort girls in London is not easy but also it is not very difficult for an eye used to this kind of adverts and to an eye that knows how to calculate a fair price.
So, if you go on London you have to be prepared with a good amount of money in order to get a premium escort girl.