Aside from no Russians can fly direct to UK presently.
Above 150ph you will find most nationalities at ever increasing price points, though likely at increasing rarity. That doesn't dispel the perception/observed prevalence that Russian girls like to charge a premium in the last 20 yrs. Quoting what an agency dictates is not the same, agencies have their own reputation to manage, selling over-priced starfish or unskilled/unenthusiastic SPs to their higher paying clients would not go down well (fnah). Rich Russians wanting Russian-speaking SPs, perhaps preferably racially specific, will skew the market offer price for a girl who qualifies e.g. white, fit, busty, exclusive, BB-friendly, free to travel...
Better to ask what kind of girls the various categories of higher spender are clamouring for e.g. the Arab expats, the City Europeans, the tech bros, the wealthy Africans, the high net worth retirees. Perhaps other UKPers who regularly drop 300+ on an hour's fun can speak to the markets they've been plundering?
Everyday Russian punters, much like the rest of us on a budget, may only have the "common" market to dip into. Maybe one of them here might be able to speak of other listings e.g. native language classifieds.
There will always be exceptions and granted my dipping of Russians is a generation out of date but I don't recall them being the warmest, sexiest or most skilled or willing. Russian-speaking Lats, Estonians, Ukrainians, etc pretty much all on average were better company and better SPs.
AW search for:
Russian, London, <55, active in last month, <=700ph returns 17 SPs! Only 1 with a substantial rep here, most with fit figures if pics real.
So looks like the "Natashas" are working almost exclusively out of "agencies" and perhaps not even those that are well known to even our vocal high spenders. Much like top notch Chinese and Japanese are behind an exclusivity curtain.
Same AW search for London <=700ph:
Thais - 72 girls (71 <-200ph)
Ukrainians - 32! Only handful matching figure and looks of the better Russians above. (28<=200ph)
Estonians - 5
Latvians - 4
Peruvians - 8 - Oof! Alessia lena looks HOT and only 180ph.
Brazilians - 596!!!! (543 <=200ph)
Chinese - 31
Spanish - 21
Romanian - 261 (247 <=200ph)
British - 1031 (674 <=200ph)
Polish - 140 (124 <=200ph)