The guide to removing the bumper is here:
http://www.corsa-c.co.uk/forum/viewtopic.php?t=4
The light are then only held in with three bolts I think it is and they will lift out. Obviously there are cables attached to light em up, just un-plug these, and hey presto, the rabbits out the hat :? Sorry light is out the car. Yeah , that's it!
The only reason for the bumper removal is because there is one bolt on the underside of the light, but Chewy changed his by loosening the bumper and letting it drop forward, but not off, and then removing the underneat headlamp bolt. It's up to you.
It's quicker just loosening the bumper, but easier if it's out of the way.
Personally, if you are not 100% sure/confident, I would suggest you remove your bumper before your mate gets there, and have a look at how it all goes together. When he gets there, just loosen your mates bumper for the swop out.
K
