Leisa Gwenllian is a force of nature as working-class heroine Effi in this big screen version of Gary Owen’s one-woman play Leisa Gwenllian is a force of nature as working-class heroine Effi in this big screen version of Gary Owen’s one-woman play T he visceral one-woman play Iphigenia in Splott by Welsh dramatist Gary Owen has overwhelmed audiences and critics since it premiered in 2015 , reimagining the sacrificial heroine Iphigenia from Greek tragedy as a young working-class woman in Cardiff