Do you have a picture of the damage? It can probably be pushed back out a fair amount if you just wanted to bodge it back to somewhere near acceptable.. But I'm fairly sure that ALL Corsa D front bumpers have the standard grill moulded in as part of the bumper, so to repair it 100% it'd be a new bumper. Unless theres a type of bumper on a Corsa D that I've never seen, lol..
A picture would help.
Dave