Identity Cards Bill

This is a genuine question—I am not clear in my own mind as to the relationship between the register and other databases on which information about individuals is held. I accept that there should be no compulsion in this, but if, for example, someone was not clear about some aspect that they wished to include on the register, could they voluntarily ask the register to seek that information from other sources? Could that be something as simple as the electoral register, the DVLA, the passport authority, or whatever?