Well they are Gwenda and Victor Wigleigh, not sure if Agatha's last name matches/is of any relation.

This is what they look like:

[hider=Them][img]http://cx.aos.ask.com/question/aq/700px-394px/can-boy-girl-identical-twins_f20c37b6ec0408c1.jpg[/img][/hider]