Use my NHS number?
Well as a regular customer of the NHS..... I haven't a f'ing clue WHAT my number is.
The way they identify me down at the GP office/Cardiac consultants/ A&E is to ask my name, my address , then my date of birth
And lo.... as if by magic my medical record appears, and a doc pokes me to see if I'm not dead yet(and calls my next of kin if I dont thump him/her one for poking me).
NHS number...... no chance mate