I happened to be doing a reccie in Liverpool today and I saw the other Polish girl (Julitka) in Berry Street, and the only scam I encountered was that Jowita and Julitka are still describing each other as "sisters".

A very decent and enjoyable punt (review to follow, when I am less knackered), but agree the location is shit if you want to be discrete. Front door is a bit manky (no bell) and building looks run-down, but the actual flat they work from is on the third floor and is very clean and tidy.
Absolutely nothing underhand or dodgy as far as I could tell, and great VFM (I was there for half an hour), and I would be happy to go back.
Pinch of salt: doesn't mean there hasn't been scamming in the past (or trouble if you do visit, for that matter), but I doubt it and they seem like a couple of reliable girls.