Your best Bet is Heading down to the Scrap yard and Collecting a New Central Locking Unit, this happened to me a while back , the box has blown or shorted itself.
the Central locking controller box it is hidden under the ECU on the Corsa.
down Where the Bonnet Catch is, take the plastic casing off and reveal the ECU , looks like a silver HDD from a computer Reove that and the Plastic Holder underneath pushes up and under some carpet behind the plastic ECU there the Central Locking Controller box is :D!!!
The same applies at the Scrapyard, they are small enough to shove up your sleeve as well ;)
Regards
Phantom
Phantom of Tynemouth, December 2006