Best possible tweak would be to search by nationality, or even better, exclude by nationalty - but the lying Sergei cunts would get round that by saying their girls are all from Italy.
Exclude by nationality would be good, but they are possibly worried about being prejudiced. It is something you can do as a private preference but dodgier as policy (they already have special rules in place for certain countries).
What I do in case anyone finds the idea helpful (or can suggest others) is use saved searches. My first call will be a search with very specific, saved parameters, English first language, age range and so on. Then I have two broader saved searches in case the more specific one doesn't yield a result. That way, it is only three clicks. Better than keying it in from scratch every time.However,
I suspect that whatever method you use for searching it will miss a few. I can do a global search (no restrictions other than, say, age and area) and then find a profile mentioned on here that fits the parameters but didn't show up in the search. I also (on and off, depending whether it suits me) will have a free email alert set up. Most of them I can delete without checking based on a thoroughly stupid profile name, but it is a way of covering maximum bases with minimum effort, hence efficiency (I hope!)
What Adultwork mostly doesn't list is sauna girls (parlours) although a few crop up. Fortunately UKP does (and occasionally the unusually sane poster on ISG will point a few out usefully as well). Girls with dusty phones of course need to advertise everywhere that allows them to or does so at a cost-effective price. Business like any other.