You can be very specific but that doesn't guarantee anything. Some girls point blank refuse to provide this service. Fortunately, they're in overwhelming minority. Some girls have a large selection of apparel and accessories and will fulfill your request to the dot. Unfortunately, they're an overwhelming minority, too. At least in the sub £200/h range, that is.
For the most part, you'll find yourself somewhere in between. Agency girls usually use (old) professional photos where they wore borrowed outfits so don't expect them to have those at hand. AW SP's will fall into that category as well if their pics look semi-pro, typically taken in a studio. If it's more like selfies or pics in front of a mirror then you might have more luck. That being said, most WG's work out of their 'work apartments' where they'll have like two sets of underwear and that's it. So if you want an outfit req, book in advance. Cause if you book 2h prior and the girl doesn't have the exact same thing she was wearing in her profile pic, then that shouldn't count towards negative.
Another point to consider is their immigration status. Local escorts whose profiles go back several years will surely have access to a larger range of clothing then those living & working out of a suitcase (thai, brazilian etc.)
However, if a girl agrees to wear something for you and then doesn't wear/have it, then that's definitely a negative. At least in my book.
Addendum: Bear in mind that often when discussing an outfit request, you're talking to a maid. Whether or not they pass your request on is another thing. Then there is also the fact where a lot of foreigners just say 'yes' to anything they don't understand. Like "What color is your hair? Yes."
