Corsa-B.uk - Vauxhall, Opel and Holden Corsa B Owners Club

Hello everyone. I just got a corsa b 1.4 16v. The car is runing fine... Today while i was looking at the engine i found a connector wich was just hanging there. The connector is from a lambda control unit...anyone knows where should be connected that wire? And another thing...where is the reverse light sensor? Is the one incircled in one of the pictures?
Click on the link for pictures
http://img818.imageshack.us/g/dsc05697.jpg/