Statistically, what's the chances of any Asian girls appearing in Glasgow, or indeed the UK, actually being Japanese? Admittedly, I'm not sure, but my gut tells me it's very, very low.
Most of these types of adverts are B&S and you'll end up seeing a quite possibly trafficked Chinese woman who speaks little to no English, paying off her "visa" by being shipped around the country, advertised as being Japanese or Korean to try and fool British punters who are assumed to be so racist that they can't tell the difference.