I know what your saying Steve. They come unstuck in London though because the Filipinas are quick to find out their true worth. There's plenty of them and they all talk to each other so they know the going rate. My wife's starting a new job on 1st July for the same money she's on at the moment but 11 hours less per week. She's delighted.
One note of caution is I always take her to interviews just to be on the safe side.