Was this function a standard function of this particular car.
If not, I have read that some tech 2 technicians can do this. These are apparently the steps.
1, tech2 screen, ENTER
2 diagnostics
3 year of car eg 2007
4 astra h
5 infotainment
6 programming
7 code index
8 program code index
9 enter
10 a part number will flash on the screen press enter
11 the type of set up will flash on the screen eg liniar resistance type b press enter
12 current code index is displayed eg code index 009 version 3
press program
13 change code index to 008 if original index is 007 or 010 if original is 009
14 press program
15 programming is complete press finish/abort
16 exit to main screen and turn off