You have confirmed that you did not receive the NIP within 14 days, but you were the driver.
It is imperative that if you were the driver that you provide your details even if the NIP is defective and also if you consider that you are not guilty of the offence. The defence to the substantive offence can be dealt with post charge/summons. You must never fill in the form for some else named on the NIP and you must never write or allow someone else to complete it in their name if you were the driver. This could lead a more serious charge which could result in imprisonment.