The oddometer and trip are electronic on the corsa, are you sure it's a bulb fault? If it is it's fairly simple to remove but you will need a set of star (torx) drives to dismantle.
remove steering column shroud, top clps on, bottom has three screws one underneath in thhe middle two on top at the front visible when the top has been removed
Remove the airbag two screws in the back of the steering wheel, unplug airbag, pull off the yellow locking tab before removing plug, make sure the ignition is off! unplug the radio controls for the steering wheel. plug is just below the retaing nut for the steering wheel.
Remove steering wheel.
Remove lower dashpanel (knee pad) two screws at the bottom in small recesses. Pull out the tray on the right hand side, this locks the panel in place the panel should now drop off.
Remove the speedo cluster shroud, one screw in the top centre and two screws at the bottom one each side of the steering column which can now be seen once the knee pad is removed, this shroud need a bit of jiggling to get ie out but be careful you don't put too much strain on the indicator or wiper stalks.
Instrument cluster is secured by two screws in the bottom and a small clip at the top.
The light bulb is right behid the oddometer and requires a quarter turn to remove it.
Might sound complicated but it will only take 15 minutes if you have the correct star drives.
Hope thiis helps.
Salemtolkein
May 2008