She May Not Leave

Hattie and Martyn are a decent, hard-working, ecologically-minded young couple. So when they meet Agnieszka, a domestic Polish paragon who's married to a bus driver back home, they take pity on her and invite her to live with them.
Soon Hattie succumbs to temptation and asks Agnieszka to baby-sit their daughter Kitty, and in no time at all she's back in full-time work. In fact life is pretty much as it was before the baby came along, except the house is cleaner and better organized thanks to modest, docile Agnieszka, who is prepared to work for a pittance, and is not too pretty for comfort. But soon things begin to sour: Martyn and Agnieszka grow closer and it occurs to Hattie that baby Kitty, given a choice, would now choose Agnieszka over her. And the downward spiral continues: visas, a marriage of convenience and even her own friends and family conspire to force Hattie out of her home and her partner's bed...