Newer Versions of VDR come with auto PID scanning.
The menu allows you to select how you want to do this. The options are
[0] = ("no");
[1] = ("names only");
[2] = ("names and PIDs");
[3] = ("add new channels");
[4] = ("add new transponders");
The option I wanted was missing. I was after an update that kept the PIDs up to date but did not change the names.... so I added it in.
The menu now contains :
[0] = ("no");
[1] = ("names only");
[2] = ("PIDs only");
[3] = ("names and PIDs");
[4] = ("add new channels");
[5] = ("add new transponders");
And the update code works with these numbers.
The patch file is available to download if anyone else would like this add on.