She is 'European' / 'Eastern European', which is agency lingo normally meaning Romanian nationality.
The photos are more than likely to be photo shopped. Be very surprised if you meet the lady who looks anything like her photos.
She is cheap because she is more than likely to be a crap service provider.
Bear in mind, £150 p/h is not cheap anyway, lots of good SP's on AW at that price or below and not likely to be pimped out / agency taking a cut from them.