Re: NI number? Why?
It is a requirement that your lifetime dose records are taken. Yes, theoretically you could do it by assigning a separate unique lifetime number that all employers and providers of dosimetry service agree on. In practice, the NI number is it: http://www.hse.gov.uk/pubns/irp2.pdf
Yes, mine too. Also innumerable henchmen who work in secret underground bases in a volcano will also doubtless have had their name and address disclosed.