All available sources indicate she was the daughter of Pagan (Pain) Peverell, Lord of Whittington
And in fact here is her duplicate: Maud Peverell, Lady of Whitting
Guy leStrange, I and Sir Guy Warin de Metz, The Bold are believed to be the same person (leStrange being his nick-name acquired through his habit of conquering new i.e. strange lands).