I came here as a fiancee and my name is NOVIE!
Anyway, you need a fill up a form from the doctors for new patients for your wife and son then they will just send you a letter after few weeks with their medical cards. Easy Peasy!
They didnt ask for any passport or any identification from me at all. Very straight forward.
I pay privately for my teeth so I dont know if its the same procedure.
http://www.nhs.uk/choiceintheNHS/You...MS1%5B1%5D.pdf