The image you refer to is not an ISO connection. ISO connections are what you have on your Corsa. They are rectangular connectors with eight connections, formed by two rows of four. The key on each connection is in a slightly different place so that you do not plug them in wrong if you have a lead with two different connectors.
Take a look at the following link, it refers to an Audi Quattro radio but it is an ISO connector and would plug into your Corsa. Connectors B and C on the diagram are the ISO connections.
http://www.isham-research.co.uk/quattro/wiring/Typ85/isopin.html
Dave
April 2006