Doubles and stand-ins ?

Hi,
First time poster here. Don’t know how to ask this question but here goes;

 I am looking for information on WW2 British military personal that, because of their resemblance to a famous or important person, would have been used as their "double" in order to protect his or her idendity, particularly the Royal Family. 

 I am conducting research for a person that believes her recently deceased Grandfather may have been one of these individuals. Are there any books or information avaliable on this subject?

Please contact me here or at; [email]gunny33@msn.com[/email] 

Regards, and thanks to anyone that may reply.

Bill Kana