You might want to read the later posts in this thread where was asking similar questions and got some hepful answers from others.
I went through this quite recently and was confused as the manual told me I had to unlock the controller. These guys set me straight!
As others have said you do need a police incident number - in my experience they are used to this and know what you are asking for. ATC will ask you to call before take off and after landing. Both were very helpful and it was all much easier than I expected.